> ## Documentation Index > Fetch the complete documentation index at: https://docs.haau3.com/llms.txt > Use this file to discover all available pages before exploring further. # List a state's counties > FHIR type-level operation `$counties` on InsurancePlan: the counties and county equivalents of a state, the District of Columbia or a territory, sorted by name, each with the five-digit FIPS code `coverage-area-county` takes. The answer is a `Parameters` resource: one `county` parameter per county, whose `code` part is a Coding in `http://terminology.hl7.org/CodeSystem/FIPS64` with the county's name as its display and whose `state` part is the state's code, then a `source` parameter naming the list: the U.S. Census Bureau's 2020 county codes. It answers whether or not a plan is sold in a county. GET only. Defined by the haau3 implementation guide (`https://haau3.com/fhir/OperationDefinition/InsurancePlan-counties`). ## OpenAPI ````yaml /api-reference/openapi.json get /v1/fhir/r4/InsurancePlan/$counties openapi: 3.1.0 info: title: haau3 Platform API version: 1.0.0-preview.4 description: >- The haau3 platform API is in preview: it may change as we build, usually to add features or improve performance. Endpoints require an API key, sent as `Authorization: Bearer `. Requests without a valid key return 401. Create a key in the dashboard at https://platform.haau3.com; a new organization starts on the free Developer plan. From 2026-11-01 a request past one of its plan's limits (requests a minute on every plan, requests a month on Developer) returns 429 with `Retry-After`. Every error under `/v1/fhir` is a FHIR `OperationOutcome` and every other error an RFC 9457 problem; https://docs.haau3.com/errors lists every status, whether to retry it, and what a method a path does not take answers. servers: - url: https://api.haau3.com description: Production security: - bearerAuth: [] tags: - name: Scheduling description: 'Provider availability (SMART Scheduling Links): slots and publishers.' - name: FHIR base description: >- What the FHIR R4 base at `/v1/fhir/r4` answers for every service on it: the `CapabilityStatement` that lists them all, and batch Bundles that carry several requests to any of them in one round trip. - name: Terminology description: >- FHIR terminology operations over the code systems listed in TerminologyCapabilities. Some are resolved from their own source when you ask; others are held here at a named release, which that resource also names. - name: Provider directory description: >- CMS's National Provider Directory as FHIR R4: practitioners and their roles, organizations, payers and insurance networks, network membership, healthcare services, locations and endpoints. Every parameter the service serves is declared here, and any other is refused by name rather than ignored. - name: Questionnaires description: >- FHIR Questionnaire, served as its source publishes it. This service holds copies of a curated set and reaches any other questionnaire its source publishes by canonical URL, as well as forms published at their own address under places this service is set up to reach. Read one by id, and build the QuestionnaireResponse in your own application. - name: Plan Benefits description: >- FHIR InsurancePlan: what a Medicare Advantage or ACA Marketplace plan covers and what a member pays, read from the files CMS publishes. Every plan names the CMS release it was read from. Read a plan by its id, or search by identifier, name, state or county, and check whether the CMS National Provider Directory lists providers in a plan's network. - name: MedList description: >- One reconciled medication list from one patient's FHIR medication records, as US Core MedicationRequests with a Provenance for each. This operation receives patient data, so send it only under an executed agreement. paths: /v1/fhir/r4/InsurancePlan/$counties: get: tags: - Plan Benefits summary: List a state's counties description: >- FHIR type-level operation `$counties` on InsurancePlan: the counties and county equivalents of a state, the District of Columbia or a territory, sorted by name, each with the five-digit FIPS code `coverage-area-county` takes. The answer is a `Parameters` resource: one `county` parameter per county, whose `code` part is a Coding in `http://terminology.hl7.org/CodeSystem/FIPS64` with the county's name as its display and whose `state` part is the state's code, then a `source` parameter naming the list: the U.S. Census Bureau's 2020 county codes. It answers whether or not a plan is sold in a county. GET only. Defined by the haau3 implementation guide (`https://haau3.com/fhir/OperationDefinition/InsurancePlan-counties`). operationId: listInsurancePlanCounties parameters: - name: state in: query required: true description: >- The two-letter USPS code of a state, the District of Columbia or a territory: `FL`. schema: type: string pattern: ^[A-Za-z]{2}$ example: FL - $ref: '#/components/parameters/XRequestId' responses: '200': description: >- A `Parameters` resource listing the state's counties, then the list's source. content: application/fhir+json: schema: $ref: '#/components/schemas/Parameters' examples: Florida's counties: summary: Florida's counties value: resourceType: Parameters parameter: - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12001' display: Alachua County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12003' display: Baker County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12005' display: Bay County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12007' display: Bradford County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12009' display: Brevard County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12011' display: Broward County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12013' display: Calhoun County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12015' display: Charlotte County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12017' display: Citrus County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12019' display: Clay County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12021' display: Collier County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12023' display: Columbia County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12027' display: DeSoto County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12029' display: Dixie County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12031' display: Duval County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12033' display: Escambia County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12035' display: Flagler County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12037' display: Franklin County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12039' display: Gadsden County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12041' display: Gilchrist County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12043' display: Glades County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12045' display: Gulf County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12047' display: Hamilton County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12049' display: Hardee County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12051' display: Hendry County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12053' display: Hernando County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12055' display: Highlands County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12057' display: Hillsborough County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12059' display: Holmes County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12061' display: Indian River County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12063' display: Jackson County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12065' display: Jefferson County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12067' display: Lafayette County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12069' display: Lake County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12071' display: Lee County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12073' display: Leon County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12075' display: Levy County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12077' display: Liberty County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12079' display: Madison County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12081' display: Manatee County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12083' display: Marion County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12085' display: Martin County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12086' display: Miami-Dade County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12087' display: Monroe County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12089' display: Nassau County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12091' display: Okaloosa County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12093' display: Okeechobee County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12095' display: Orange County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12097' display: Osceola County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12099' display: Palm Beach County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12101' display: Pasco County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12103' display: Pinellas County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12105' display: Polk County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12107' display: Putnam County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12113' display: Santa Rosa County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12115' display: Sarasota County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12117' display: Seminole County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12109' display: St. Johns County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12111' display: St. Lucie County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12119' display: Sumter County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12121' display: Suwannee County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12123' display: Taylor County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12125' display: Union County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12127' display: Volusia County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12129' display: Wakulla County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12131' display: Walton County - name: state valueString: FL - name: county part: - name: code valueCoding: system: http://terminology.hl7.org/CodeSystem/FIPS64 code: '12133' display: Washington County - name: state valueString: FL - name: source valueString: >- U.S. Census Bureau, 2020 FIPS codes for counties and county equivalents: https://www2.census.gov/geo/docs/reference/codes2020/national_county2020.txt headers: X-Request-Id: $ref: '#/components/headers/XRequestId' X-Correlation-Id: $ref: '#/components/headers/XCorrelationId' '400': description: >- A state that is not two letters, a missing or repeated `state`, or another parameter, named. content: application/fhir+json: schema: $ref: '#/components/schemas/OperationOutcome' headers: X-Request-Id: $ref: '#/components/headers/XRequestId' X-Correlation-Id: $ref: '#/components/headers/XCorrelationId' '401': $ref: '#/components/responses/FhirUnauthorized' '404': description: No state, district or territory has this code. content: application/fhir+json: schema: $ref: '#/components/schemas/OperationOutcome' headers: X-Request-Id: $ref: '#/components/headers/XRequestId' X-Correlation-Id: $ref: '#/components/headers/XCorrelationId' '406': $ref: '#/components/responses/FhirNotAcceptable' '429': $ref: '#/components/responses/FhirTooManyRequests' '500': $ref: '#/components/responses/FhirServerError' '503': $ref: '#/components/responses/FhirUnavailable' x-codeSamples: - lang: bash label: cURL source: > curl "https://api.haau3.com/v1/fhir/r4/InsurancePlan/\$counties?state=FL" \ -H "Authorization: Bearer $HAAU3_API_KEY" - lang: typescript label: TypeScript source: > import { Haau3 } from "@haau3/sdk"; const haau3 = new Haau3(); // reads HAAU3_API_KEY const parameters = await haau3.listInsurancePlanCounties({ state: "FL" }); for (const parameter of parameters.parameter ?? []) console.log(parameter.name); - lang: python label: Python source: | from haau3 import Haau3 client = Haau3() # reads HAAU3_API_KEY parameters = client.list_insurance_plan_counties(state="FL") for parameter in parameters.get("parameter", []): print(parameter.get("name")) - lang: go label: Go source: "package main\n\nimport (\n\t\"context\"\n\t\"fmt\"\n\t\"log\"\n\n\t\"github.com/haau3/haau3-go\"\n)\n\nfunc main() {\n\tctx := context.Background()\n\tclient, err := haau3.NewClient() // reads HAAU3_API_KEY\n\tif err != nil {\n\t\tlog.Fatal(err)\n\t}\n\tparameters, err := client.ListInsurancePlanCounties(ctx, haau3.ListInsurancePlanCountiesParams{State: \"FL\"})\n\tif err != nil {\n\t\tlog.Fatal(err)\n\t}\n\tfor _, parameter := range parameters.Parameter {\n\t\tif parameter.Name != nil {\n\t\t\tfmt.Println(*parameter.Name)\n\t\t}\n\t}\n}\n" components: parameters: XRequestId: name: X-Request-Id in: header required: false schema: type: string format: uuid description: >- An id of your own for this request, as a UUID. It comes back in the `X-Correlation-Id` header and is kept with haau3's record of the request. Any value that is not a UUID is ignored. See https://docs.haau3.com/errors#request-ids. schemas: Parameters: type: object description: A FHIR R4 [Parameters](https://hl7.org/fhir/R4/parameters.html). properties: resourceType: type: string const: Parameters parameter: type: array items: type: object additionalProperties: true required: - resourceType additionalProperties: true OperationOutcome: type: object description: >- A FHIR R4 [OperationOutcome](https://hl7.org/fhir/R4/operationoutcome.html). properties: resourceType: type: string const: OperationOutcome issue: type: array items: type: object properties: severity: type: string enum: - fatal - error - warning - information code: type: string details: type: object properties: text: type: string additionalProperties: true diagnostics: type: string expression: type: array items: type: string required: - severity - code additionalProperties: true required: - resourceType - issue headers: XRequestId: description: >- The id haau3 gave this request, a UUID, on every response. Quote it in a question about the response. A problem carries the same id as its `instance`. schema: type: string format: uuid XCorrelationId: description: The `X-Request-Id` you sent, when it was a UUID. schema: type: string format: uuid responses: FhirUnauthorized: description: Missing or invalid API key. content: application/fhir+json: schema: $ref: '#/components/schemas/OperationOutcome' headers: WWW-Authenticate: description: >- The scheme to authenticate with: `Bearer realm="api.haau3.com"`, with `error="invalid_token"` when a key was sent and not recognised. schema: type: string X-Request-Id: $ref: '#/components/headers/XRequestId' X-Correlation-Id: $ref: '#/components/headers/XCorrelationId' FhirNotAcceptable: description: >- The request asked for a format other than JSON (`Accept` or `_format`), or for a FHIR release this endpoint does not serve (the `fhirVersion` media-type parameter). content: application/fhir+json: schema: $ref: '#/components/schemas/OperationOutcome' headers: X-Request-Id: $ref: '#/components/headers/XRequestId' X-Correlation-Id: $ref: '#/components/headers/XCorrelationId' FhirTooManyRequests: description: >- A limit of the organization's plan was reached: its requests a minute, or the Developer plan's requests a month. Send the request again after `Retry-After`, which for the monthly limit runs to the 1st of the next month (UTC). content: application/fhir+json: schema: $ref: '#/components/schemas/OperationOutcome' headers: Retry-After: description: How many seconds to wait before sending the request again. schema: type: integer minimum: 0 X-Request-Id: $ref: '#/components/headers/XRequestId' X-Correlation-Id: $ref: '#/components/headers/XCorrelationId' FhirServerError: description: The server failed to process this request. content: application/fhir+json: schema: $ref: '#/components/schemas/OperationOutcome' headers: X-Request-Id: $ref: '#/components/headers/XRequestId' X-Correlation-Id: $ref: '#/components/headers/XCorrelationId' FhirUnavailable: description: >- The API key could not be checked just now. Send the request again after `Retry-After`. content: application/fhir+json: schema: $ref: '#/components/schemas/OperationOutcome' headers: Retry-After: description: How many seconds to wait before sending the request again. schema: type: integer minimum: 0 X-Request-Id: $ref: '#/components/headers/XRequestId' X-Correlation-Id: $ref: '#/components/headers/XCorrelationId' securitySchemes: bearerAuth: type: http scheme: bearer description: >- Your platform API key (`haau3_sk_…`), sent as `Authorization: Bearer `. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.