Parcels
Isopleth serves public parcel records in the states that publish them free and statewide: owner, situs and mailing address, land use, zoning (where published), assessed, land and improvement value, last sale, year built and legal description, plus the boundary and calculations from it (acres, square feet, perimeter, centroid, bounding box, compactness, minimum rectangle). Each response names the publisher, licence and data vintage.
Live now: 10 states,
41,208,084 parcels (table updated 2026-10-29). Columns are what each publisher
releases, so they vary by state: check the fill rates below or GET /v1/parcels/coverage.
Enrich: the parcel at a place
POST /v1/enrich with exactly one of lat+lng, address,
parcel_id (from an earlier result) or apn+state (optionally county).
Add fields and/or a preset to compute point fields at the parcel's interior point in the same
call. A point inside stacked parcels (condos) returns the smallest parcel plus additional_parcels. An
address is geocoded, then matched to the parcel with the same house number and street nearby.
curl https://api.isopleth.dev/v1/enrich -H "Authorization: Bearer $ISOPLETH_KEY" -H "Content-Type: application/json" \
-d '{"address": "1600 Pennsylvania Ave NW, Washington, DC", "fields": ["elevation"], "include_geometry": false}'
Search: parcels that match
POST /v1/search with state (or a bbox/polygon) and any of
county, acres_min/max, owner (prefix or contains),
usecode, land_use, value_min/max, land_value_*,
sale_price_*, sale_date_*, year_built_*, zip, city, and
generic filters ({"field", "op", "value"} with op eq ne lt lte gt gte in between contains
starts_with exists missing). Up to 100 parcels per page; pass next_cursor back as cursor
for the next page.
curl https://api.isopleth.dev/v1/search -H "Authorization: Bearer $ISOPLETH_KEY" -H "Content-Type: application/json" \
-d '{"state": "TX", "county": "Travis", "acres_min": 40, "land_use": "agricultural", "limit": 50}'
Lookups
An enrich that matches a parcel is 1 lookup, plus 1 per started block of
50 point fields. A search page that returns parcels is 1
lookup. No match, an empty page and errors are free, and so is /v1/parcels/coverage. MCP clients get the
same through parcel_enrich, parcel_search and parcel_coverage.
Coverage
| state | parcels | counties | owner | mailing | value | sale | land use | zoning | publisher | licence | vintage | refresh |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| CT | 1,320,655 | 9 | 98% | 98% | 97% | 58% | 96% | 94% | CT GIS Office / Office of Policy and Management; 169 municipalities | Public, attribution | 2026 parcel + CAMA collection | annual |
| DC | 137,400 | 1 | 97% | 92% | 96% | 76% | 96% | — | District of Columbia OCTO / DC GIS; Office of Tax and Revenue | Public, attribution | OTR extract through 2026-10-16 | quarterly |
| MA | 2,559,636 | 14 | 99% | 99% | 98% | 98% | 100% | 73% | MassGIS (Bureau of Geographic Information); 351 municipal assessors | Public, attribution | Assessor FY2018-FY2027 depending on town | annual |
| MN | 2,710,201 | 72 | 78% | 61% | 78% | 38% | — | — | Minnesota Geospatial Information Office (MnGeo); 59 opt-in counties | Open data, attribution | Compiled 2026-08/09; county acquisition dates vary (59 of 87 counties) | quarterly |
| NJ | 3,481,240 | 21 | — | 88% | 88% | 80% | 88% | — | NJ Office of GIS (NJOGIS); NJ Treasury MOD-IV tax list; counties | Public, attribution | Parcel publish dates 2023-2026 by county; MOD-IV tax attributes joined | annual |
| NY | 3,827,529 | 59 | 100% | 77% | 66% | — | 100% | — | NYS ITS Geospatial Services; NYS DTF Office of Real Property Tax Services; contributing counties | Public, attribution | 2025 assessment roll (published May 2026; 38 of 62 counties) | annual |
| NC | 5,938,804 | 100 | 99% | 98% | 95% | 43% | 53% | — | NC Center for Geographic Information and Analysis (NC OneMap); NC counties | Free and unrestricted use | County submissions aggregated by NC OneMap (item modified 2026-09-17) | quarterly |
| TX | 14,336,268 | 254 | 97% | 95% | 80% | — | 69% | — | Texas Geographic Information Office (TxGIO) / county appraisal districts | CC0-1.0 | StratMap 2025 Land Parcels (county acquisitions through mid-2025; 253 of 254 counties, Donley missing) | semiannual |
| WA | 3,321,713 | 39 | — | — | 95% | — | 98% | — | WaTech (Washington Parcels Project); counties | Public, attribution | Current annual compilation | annual |
| WI | 3,574,638 | 72 | 98% | 96% | 88% | — | 88% | — | Wisconsin State Cartographer's Office / WLIP at DOA | Public, attribution | V12 (2026 release; tax roll 2025) | annual |
Percentages are the share of parcels with that column filled. A dash means the publisher does not release it.
Being loaded: AR, CO, DE, FL, HI, IN, ME, MD, MT, NE, NH, ND, OH, UT, VT, VA, WV, WY.
Not offered:
- AK: Not statewide (20 local sources); licensing is per originating source.
- ID: Only 13 of 44 counties; terms defer to the Idaho Parcel Data Exchange Standard (not reviewed).
- TN: Comptroller's public layer says it is not intended for commercial use (bulk download recommended for commercial purposes).
No free statewide layer: AL, AZ, CA, GA, IL, IA, KS, KY, LA, MI, MS, MO, NV, NM, OK, OR, PA, RI, SC, SD.
Good to know
- Records are copies of what each county or state publishes, refreshed on the cadence above. They can lag recent sales and splits, and they are not a title search, survey or appraisal.
parcel_idcan change when a state is refreshed. Storeapn+stateto look a parcel up again.- Road frontage is not computed yet.
- Owner names are personal data in many records. You may not use them for decisions about a person's credit, insurance, housing or employment, and you must follow the publisher's terms and any state limits on use.