Tribal Land Jurisdiction Screener — Reservation, Trust Land & Section 106 THPO Check

Batch point-in-polygon screen of coordinates against every American Indian reservation, off-reservation trust land, Hawaiian Home Land, and Alaska Native / tribal statistical area published by the U.S. Census Bureau TIGERweb AIANNH layer. One row per coordinate, with the flags a consultant actually needs: Section 106 THPO consultation, civil/regulatory jurisdiction, and trust-land lending & title review.

Keyless. No API key, no scraping, no rate-limit dance.

This is a screening tool, not a jurisdictional determination. It tells you whether a coordinate intersects a published boundary. It does not tell you who has jurisdiction. Confirm Indian-country status, civil/regulatory jurisdiction and trust or restricted-fee title with the affected Tribe, the BIA, the Tribal Historic Preservation Office and legal counsel.

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The distinction this actor exists to make

Census publishes two very different things in one layer, and conflating them is the most common error in tribal-land screening:

	What it is	What it means for you
Legal land tenure — federal & state reservations, off-reservation trust land, Hawaiian Home Lands (MTFCC G2100, G2120)	A real land-tenure boundary. Indian country.	Distinct tribal tax, permitting, gaming (IGRA) and land-into-trust regimes. Trust land has its own foreclosure, mortgage, leasehold and title rules (BIA-approved leases, HUD Section 184).
Statistical tabulation area — ANVSA, OTSA, SDTSA, TDSA, joint-use areas (G2130–G2170)	A Census geography for tabulation only.	Not a jurisdiction boundary. Still a strong signal for Section 106 outreach, but it does not by itself establish jurisdiction or title.

Every row states which one it hit, in legal_or_statistical, and records how it decided in land_tenure_basis.

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What v1.1 fixed (2026-08-01)

This actor was hardened against the class of bug that bills a buyer for a confident wrong answer while the run reports SUCCESS.

• A failed lookup can no longer report "not in tribal jurisdiction." The previous version fell back to a secondary source and, when that source found nothing, emitted a billable row reading on_tribal_land: false, section106_thpo_consultation: false, error: null. Measured live: the fallback (USGS TNM) is missing 73 of the 704 Census areas — 100% of Oklahoma Tribal Statistical Areas, 100% of State Designated Tribal Statistical Areas, 100% of Tribal Designated Statistical Areas, plus Shakopee Mdewakanton, Twenty-Nine Palms and Rappahannock trust land. Its silence is now reported as null (undetermined) with a reason, never as a clear.
• Five live drift assertions run before any row exists, and fail the run if the source is not behaving as verified: layer identity and field list, national polygon count in band, the MTFCC vocabulary still containing all seven decoded codes, a positive canary (Navajo Nation must resolve to GEOID 2430M), and a negative control (downtown Dallas must return zero). The negative control is not decoration: a malformed spatial filter on this service returns HTTP 200 with all 704 national features and no error.
• Billing is gated before the write. Rows are buffered; if no asset could be determined the run fails and pushes nothing.
• 43 new output fields from attributes the actor was already fetching on every run and discarding, including the reservation-vs-trust-land component, the states an area spans, and the ANSI/GNIS identifier.
• Near-boundary proximity: a clear point now reports the nearest tribal area and how close it is. A parcel adjacent to a reservation still has consultation and access implications.

Offline suite: 97 test blocks / 452 assertions, every regression mutation-verified.

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Who uses this

• Section 106 / NHPA consultants and cultural-resource firms — decide SHPO vs THPO routing across a whole project footprint in one call.
• Energy, transmission and infrastructure siting — screen a route or a site portfolio before land agents start work.
• Land title, ALTA and lending due diligence — trust and restricted-fee land carries distinct foreclosure, mortgage and leasehold rules.
• Environmental review (NEPA/ESA) teams — one more overlay in the constraints stack, keyed to the same coordinates as your other screens.
• AI agents — a clean, chainable MCP tool (see below).

Example input

{
  "assets": [
    { "lat": 36.07,   "lon": -109.55,   "label": "Navajo Nation, AZ" },
    { "lat": 35.5281, "lon": -108.7426, "label": "Gallup, NM" },
    { "lat": 35.92,   "lon": -94.97,    "label": "Tahlequah, OK" },
    { "lat": 32.7791, "lon": -96.8,     "label": "Downtown Dallas, TX" }
  ],
  "maxAssets": 500,
  "proximityCheck": true,
  "proximityRadiusMiles": 10
}

Returns: Navajo Nation (legal land tenure, reservation and off-reservation trust land, spanning AZ/NM/UT); Gallup clear but with the Navajo Nation within 2 miles; Tahlequah inside the Cherokee OTSA (statistical, §106 flagged, jurisdiction not flagged); Dallas clear with nothing within 10 miles.

Input fields

Field	Type	Description
assets	array (required)	Points to screen. Each is { lat, lon, label? } in WGS84 decimal degrees. One billable row per asset.
maxAssets	integer	Safety cap on how many assets to screen. Default 500, clamped 1-5000.
proximityCheck	boolean	Also find the nearest tribal area for points that are not inside one. Default true. Never runs on a point already inside an area.
proximityRadiusMiles	integer	How far to search outward from a clear point. Default 10, clamped 1-100.

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Output fields

One row per screened asset. Every field tolerates null. null means "not checked". false means "checked, and the answer is negative."

Identity

Field	Description
asset_label	Your label for the point (auto-generated if omitted).
asset_lat	Screened latitude (WGS84).
asset_lon	Screened longitude (WGS84).
checked_at	UTC timestamp of the run.

The verdict

Field	Description
on_tribal_land	true inside any AIANNH area, false verified clear, null if no source could answer.
is_reservation_or_trust_land	Any intersecting area is legal Indian country (federal/state reservation, off-reservation trust land, Hawaiian Home Land).
is_statistical_area	Any intersecting area is a Census tabulation geography (ANVSA/OTSA/SDTSA/TDSA/joint-use) - approximate, not a jurisdiction boundary.
section106_thpo_consultation	Any tribal-area hit: NHPA Section 106 cultural-resource review may route through the THPO rather than the SHPO.
civil_regulatory_jurisdiction	On legal reservation/trust land: distinct tribal tax, permitting, gaming (IGRA) and land-into-trust regimes may apply.
lending_title_review	On legal reservation/trust land: distinct foreclosure, mortgage, leasehold and title rules.
verdict_basis	Plain-language audit trail for how the verdict was reached - including why it is undetermined when it is.
land_tenure_basis	How the legal-vs-statistical call was derived: census_aiannh_mtfcc (authoritative) or a labelled fallback basis.

The primary intersecting area

Field	Description
area_name	Short name (Census BASENAME), e.g. Navajo Nation.
area_full_name	Full Census NAME, e.g. Navajo Nation Reservation and Off-Reservation Trust Land.
area_type_code	MTFCC, e.g. G2100.
area_type	Decoded MTFCC: federal reservation / ORTL, Hawaiian Home Land, ANVSA, OTSA, SDTSA, TDSA, joint-use area.
legal_or_statistical	Legal land tenure or Statistical tabulation area.
land_tenure_class	Reservation / Trust land, Statistical area, or Alaska Native Corporation.
reservation_authority	Federal or State, from Census FSRFLG.
geoid	Census AIANNH GEOID, e.g. 2430M.
aiannh_code	Census AIANNH area code, e.g. 2430.
aiannh_class_code	Raw Census AIANNHCC (D1/D2/D3/D4/D6/D9/E1/F1/D0).
aiannh_class	Decoded AIANNHCC, e.g. Federal American Indian reservation with off-reservation trust land.
aiannh_component_code	Raw Census AIANNHCOMP (R/T/M) exactly as published.
aiannh_component	Interpreted reservation vs trust-land split - only for legal land-tenure areas; null on statistical areas, where the code carries no tenure meaning.
has_reservation_component	Area includes a reservation component.
has_trust_land_component	Area includes off-reservation trust land.
aiannh_ansi_code	Census AIANNHNS - the ANSI/GNIS national identifier. Joins to USGS GNIS.
lsad_code	Raw Census LSADC.
lsad_description	Decoded designation Census appends to the base name: Reservation, Rancheria, Pueblo, Colony, Trust Land, OTSA, SDTSA, ANVSA, Hawaiian Home Land.
functional_status_code	Raw Census FUNCSTAT (A/N/S).
functional_status	Decoded: active governmental unit, nonfunctioning legal entity, or statistical entity.

Geography

Field	Description
land_area_sqm	Land area in square metres (Census AREALAND, published as a string, parsed defensively).
land_area_sqmi	Land area in square miles.
water_area_sqm	Water area in square metres (AREAWATER).
water_area_sqmi	Water area in square miles.
total_area_sqmi	Land plus water, square miles.
centroid_lat	Census CENTLAT. A centroid can fall outside a concave polygon.
centroid_lon	Census CENTLON.
interior_point_lat	Census INTPTLAT - a point guaranteed to fall inside the polygon. Use this for a map pin or a re-query.
interior_point_lon	Census INTPTLON.
state_fips_codes	Every state the area extends into, as 2-digit FIPS.
states	The same, as USPS codes. A reservation spanning states means several regulators and several SHPOs.
state_count	How many states the area spans.
spans_multiple_states	True when the area crosses a state line.

All overlapping areas

Field	Description
overlapping_area_count	How many AIANNH areas contain the point (a joint-use area can sit on top of its constituent areas).
overlapping_areas	Every containing area, each with name, full name, type, MTFCC, tenure class, legal-vs-statistical, component and GEOID.

Near-boundary proximity (clear points only)

Field	Description
proximity_checked	A buffered near-boundary search actually ran for this point.
proximity_radius_miles	Radius used.
nearest_area_within_miles	The narrowest tested band in which a tribal area appears - a band, not an exact distance.
nearest_area_name	The most significant tribal area inside the radius.
nearest_area_full_name	Its full Census name.
nearest_area_type	Its decoded type.
nearest_area_type_code	Its MTFCC.
nearest_area_geoid	Its Census GEOID.
nearest_area_land_tenure_class	Whether it is legal reservation/trust land or a statistical area.
near_boundary	A tribal area lies within 1 mile.
nearby_area_count	How many tribal areas fall inside the radius.
nearby_areas	All of them, with name, type, tenure class and GEOID.

Source accountability

Field	Description
answered_by	census, tnm_fallback, or none.
census_status	ok / unavailable / not_attempted for the primary Census AIANNH query.
census_error	Why the primary failed, when it did. null on a healthy run - that is good news, not an empty column.
tnm_status	Same for the USGS TNM fallback. Only attempted when the primary fails.
tnm_error	Why the fallback failed, when it was tried.
sources_attempted	Per-source outcome trail, e.g. census:ok, usgs_tnm:not_attempted.
coverage_complete	true when the authoritative Census layer answered. false when only the incomplete fallback did. null when nothing did.
partial_results	The primary did not answer for this point.
reference_layer_feature_count	How many polygons the Census layer held at run time (704 as of 2026-08-01) - so you can spot an upstream that has silently shrunk.
source	Which source produced the row.
source_url	The Census AIANNH layer used.
error	Error message for an invalid coordinate or a failed lookup; null on success.
disclaimer	Informational-use disclaimer.

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Data source

• Primary: U.S. Census Bureau TIGERweb AIANNHA MapServer, layer 47 - American Indian, Alaska Native, and Native Hawaiian Areas. 704 polygons nationally. Verified as a true union of the per-type layers by point-in-polygon testing the interior point of all 869 polygons in layers 2-10: zero misses.
• Fallback: USGS The National Map govunits layer 28, Native American Area (Large-Scale). Used only when the primary is unreachable, and explicitly labelled as incomplete on any row it answers.

Boundaries are as published by Census and can lag the ground truth. Statistical areas are tabulation geographies, not jurisdiction boundaries.

Use as an MCP tool

This actor is exposed to AI agents through mcp.apify.com. The input schema is small (a list of {lat, lon, label}) and every output field carries a description, so an agent can call it and read the result without extra prompting. It composes naturally with the other screeners below: feed the same coordinate list to each and join on asset_label.

Pricing

Pay per result - $8 per 1,000 rows (one row per screened coordinate), with graduated discounts on paid Apify plans. A failed run emits nothing and bills nothing.

Related actors (same coordinate list, different overlay)

• NRHP Historic Place Screener - National Register listings and districts; the other half of a Section 106 screen.
• PAD-US Protected Lands Screener - federal, state and tribal protected-area management status.
• BLM Sage-Grouse Siting Screener - habitat management areas for western energy siting.
• Site Due Diligence Bundle - 20 environmental and regulatory layers for one coordinate in a single call.

FAQ

Does a hit mean the Tribe has jurisdiction over my site? No. It means the coordinate intersects a published boundary. Jurisdiction depends on land status, the parties involved, and the activity. Read legal_or_statistical first, then talk to the Tribe, the BIA and counsel.

What is the difference between a reservation and off-reservation trust land? Both are legal Indian country, but trust land is held in trust by the United States outside reservation boundaries and carries its own lease, mortgage and title rules. aiannh_component tells you which the area contains - reservation only, trust land only, or both.

Why did a point in Oklahoma come back as a statistical area? Much of eastern Oklahoma is covered by Oklahoma Tribal Statistical Areas, which Census publishes for tabulation. They flag Section 106 outreach but do not by themselves establish jurisdiction. The row says so explicitly.

What happens if the Census service is down? The run fails with a message naming the failure, and bills nothing. It will not fall back to a source that cannot see 10% of the country and call your site clear.

Why is on_tribal_land sometimes null? Because nothing verified it. Either the coordinate was invalid, or the primary source was unavailable and only the incomplete fallback answered. null is not false - read verdict_basis for the reason.

Can I screen a whole portfolio? Yes - up to 5,000 coordinates per run, one billable row each.