Jurisdictions

A jurisdiction is a lowercase code used to group and filter Check's tax-related resources geographically. It is either fed (federal) or a lowercased ISO 3166-2:US region code.

Local taxes use their state's code. A Pennsylvania borough's Local Services Tax has a jurisdiction of pa, so filtering taxes or agencies by jurisdiction=pa returns that state's state and local entries together.

For how jurisdictions relate to taxes and agencies, see the Taxes, Agencies, and Jurisdictions guide.

Jurisdiction codes

Code	Region
`fed`	Federal
`al`	Alabama
`ak`	Alaska
`az`	Arizona
`ar`	Arkansas
`ca`	California
`co`	Colorado
`ct`	Connecticut
`de`	Delaware
`dc`	District of Columbia
`fl`	Florida
`ga`	Georgia
`hi`	Hawaii
`id`	Idaho
`il`	Illinois
`in`	Indiana
`ia`	Iowa
`ks`	Kansas
`ky`	Kentucky
`la`	Louisiana
`me`	Maine
`md`	Maryland
`ma`	Massachusetts
`mi`	Michigan
`mn`	Minnesota
`ms`	Mississippi
`mo`	Missouri
`mt`	Montana
`ne`	Nebraska
`nv`	Nevada
`nh`	New Hampshire
`nj`	New Jersey
`nm`	New Mexico
`ny`	New York
`nc`	North Carolina
`nd`	North Dakota
`oh`	Ohio
`ok`	Oklahoma
`or`	Oregon
`pa`	Pennsylvania
`ri`	Rhode Island
`sc`	South Carolina
`sd`	South Dakota
`tn`	Tennessee
`tx`	Texas
`ut`	Utah
`vt`	Vermont
`va`	Virginia
`wa`	Washington
`wv`	West Virginia
`wi`	Wisconsin
`wy`	Wyoming

Canonicalization

Check is consolidating every resource onto this single canonical jurisdiction code — fed or a lowercased ISO 3166-2:US region code.

Why

Across Check's APIs, the same idea of a jurisdiction has been represented in several different ways, with identifiers that do not align from one resource to another — opaque jur_ IDs in some places, uppercase abbreviations in others, and a bare ?state= filter elsewhere. That makes it hard to reliably join or roll data up to a jurisdiction across resources.

Standardizing on one canonical code fixes that: a single, human-readable value means the same thing everywhere, so you can group filings, taxes, parameters, and elections by jurisdiction with confidence. It is also the foundation the newer reference resources (Tax and Agency) and future agency-referencing resources are built on.

Impacted resources

The table below maps each legacy jurisdiction representation to its canonical replacement:

Resource	Legacy representation	Canonical replacement
Company / employee tax elections	`jur_` ID plus an uppercase `jurisdiction_abbreviation`	`jurisdiction` code
Tax parameters	`jurisdiction` as a `jur_` ID	`jurisdiction` code
Reciprocity elections	`jur_` ID plus a non-standard `jurisdiction_name`	`jurisdiction` code
Applied-for tax params report	bare uppercase string (e.g. `"AL"`)	`jurisdiction` code
`company_tax_params/{id}/jurisdictions`	`{ id, label }` object shape	`jurisdiction` code
Filings	`?state=` query filter	`?jurisdiction=` query filter

Workplace.address_state is not changing. It is the state of a physical address (an uppercase USPS code).

🚧
Tax elections are the most sensitive case: their jurisdiction is a jur_ ID, and many integrations join tax-election data to the tax catalog. If you depend on the legacy jur_ IDs or uppercase abbreviations anywhere, flag it to your Check contact so we can sequence your migration.

How the migration rolls out

Wherever possible, these changes are additive — a new canonical field appears. Where a representation actually changes, Check runs the canonical and legacy fields in parallel and coordinates the cutover with each partner before sunsetting the legacy form. This does not require a new API version. If you maintain an integration against any of the resources above, your Check contact will work with you to schedule the transition.