Where every number comes from, and what it cannot tell you.

Montana State Library

Coverage

Statewide, all 56 counties

Upstream updates

Parcel geometry and ownership refreshed from county assessors on a rolling basis; valuation follows the Department of Revenue reappraisal cycle.

We refresh

monthly

Verified

2026-08-14

What it cannot tell you. The cadastral framework is an assessment and taxation record, not a survey. Boundaries are mapped to assessor accuracy and routinely differ from a surveyed line by feet and occasionally by much more. Ownership reflects the last processed transfer, so a recent sale may not appear. It carries no easements, no covenants, and no legal-access information.

Layers consumed: 1 (Parcels)

U.S. Geological Survey

Coverage

Statewide. Best available resolution varies by collection — 1 m lidar where flown, 10 m or 30 m elsewhere.

Upstream updates

Continuously improved as new lidar collections are published; a given area changes only when re-flown.

We refresh

annually

Verified

2026-08-14

What it cannot tell you. A bare-earth elevation surface. It does not know about fill, cut, existing grading, or anything built since the collection was flown. Slope computed from it describes the mapped landform, not a graded building pad, and cannot see a soft spot, a spring, or bedrock an inch below the surface.

USDA Natural Resources Conservation Service

Coverage

Nearly statewide. A small number of Montana survey areas remain unmapped or are mapped only at the coarser STATSGO scale.

Upstream updates

Annual SSURGO refresh, typically published in the autumn.

We refresh

annually

Verified

2026-08-14

What it cannot tell you. SSURGO is mapped for land-management planning at roughly 1:24,000. The smallest reliably mapped unit is a few acres, so a single building envelope can sit entirely inside a soil inclusion the map never shows. It is not a geotechnical investigation and not a percolation test, and NRCS says so directly. Its septic and construction ratings are screening ratings, not determinations.

Federal Emergency Management Agency

Coverage

Only where FEMA has mapped. Large areas of rural Montana are unmapped, which is not the same as being outside a floodplain.

Upstream updates

Amended continuously through LOMRs and periodic countywide map revisions.

We refresh

monthly

Verified

2026-08-14

What it cannot tell you. A regulatory insurance and floodplain-management map, not a hydrologic study of a specific parcel. Being outside a mapped high-risk zone is not an absence of flood risk — roughly a quarter of national flood claims come from outside mapped high-risk areas. Unmapped areas carry no determination at all. Local flooding from small drainages, alluvial fans, ice jams and irrigation infrastructure is frequently not modelled.

Layers consumed: 28 (Flood Hazard Zones)

U.S. Fish and Wildlife Service

Coverage

Statewide, with highly variable mapping vintage and source imagery scale.

Upstream updates

Updated by project area as new mapping is completed; much Montana mapping is decades old.

We refresh

quarterly

Verified

2026-08-14

What it cannot tell you. NWI is photo-interpreted from aerial imagery and is explicitly NOT a jurisdictional wetland determination. USFWS states there is no attempt to define the limits of federal or state jurisdiction. Small wetlands, narrow riparian strips and forested wetlands are systematically under-mapped. Only a delineation by a qualified consultant, and a jurisdictional call by the Army Corps, answers the regulatory question.

Layers consumed: 0 (Wetlands)

U.S. Bureau of Land Management

Coverage

National. Federal, state and tribal surface management agency. Returns no features over private land, which is the correct answer rather than a gap.

Upstream updates

Periodic, as agency holdings change.

We refresh

quarterly

Verified

2026-08-14

What it cannot tell you. Surface management agency only. It does not resolve split-estate mineral ownership, does not carry lease status, and does not tell you whether a public parcel is legally accessible — public land touching a boundary is not a right of entry.

Layers consumed: 1 (Surface Management Agency)

Montana State Library, Montana Department of Transportation

Coverage

Statewide road centrelines.

Upstream updates

Ongoing.

We refresh

quarterly

Verified

2026-08-14

What it cannot tell you. A centreline geometry and classification dataset. It carries no easement, no recorded right of way, no legal access status, and frequently no maintenance responsibility. A line on this layer reaching a parcel is evidence of a physical route, and is not evidence of a right to use it.

Layers consumed: 0 (Montana Road Centerline)

Montana State Library

Coverage

Statewide, uneven by county.

Upstream updates

Ongoing, county-supplied on the NG911 schema.

We refresh

quarterly

Verified

2026-08-14

What it cannot tell you. Structure points and address points are compiled from county sources at differing vintages. A missing structure does not mean vacant ground, and an address point is not proof a legal address has been assigned.

Layers consumed: 0 (Montana Structures and Addresses)

U.S. Geological Survey

Coverage

Statewide streams, rivers and waterbodies at NHDPlus High Resolution.

Upstream updates

Ongoing stewardship.

We refresh

quarterly

Verified

2026-08-14

What it cannot tell you. Mapped hydrography at 1:24,000. Intermittent and ephemeral channels are inconsistently captured, small irrigation ditches are often absent or indistinguishable from natural channels, and the mapped line does not establish an ordinary high-water mark, a setback, or a jurisdictional call.

Layers consumed: 3 (NetworkNHDFlowline)

Montana State Library

Coverage

Statewide counties, incorporated places, and fire districts.

Upstream updates

As boundaries change.

We refresh

quarterly

Verified

2026-08-14

What it cannot tell you. City limits change by annexation, and the mapped line can lag the ordinance. Whether a parcel is inside city jurisdiction is determined by the municipality, not by this layer. Fire district mapping shows a service boundary and says nothing about response time, staffing, or whether a district will commit to a rural address.

Layers consumed: 5 (Montana County Boundaries), 7 (Incorporated Cities and Towns), 45 (Fire Districts)

Montana DNRC

Coverage

Varies. Montana's own effective SFHA compilation, which is a useful cross-check against the federal layer rather than a replacement for it.

Upstream updates

As studies and local ordinances are adopted.

We refresh

quarterly

Verified

2026-08-14

What it cannot tell you. Montana floodplain regulation is administered locally by county and municipal floodplain administrators. Neither the state layer nor the FEMA layer substitutes for that administrator's written determination on a specific parcel.

Layers consumed: 14 (Effective Special Flood Hazard Area)

Montana State Library

Coverage

Montana-specific and spatially queryable. Preferred over the national NCED, whose public service rejects geometry queries.

Upstream updates

Periodic compilation; the current edition is dated January 2025.

We refresh

annually

Verified

2026-08-14

What it cannot tell you. A compilation of easements reported to the state. Participation is not universal and many private easements are absent. Boundaries are approximate and the easement's actual terms are never included — two easements of identical footprint can permit completely different development. The absence of an easement here is not evidence that a parcel is unencumbered; only a title search establishes that.

Layers consumed: 0 (Conservation easements by county)

County-published records (varies by county)

Montana counties differ enormously in what they regulate and what they publish. Zoning, building permits, and sanitation review are separate authorities that do not share systems. Where a county does not publish machine-readable data we say so and name the office to call, rather than inferring a rule that may not exist.

Montana Water Report

Summarised here. This platform does not re-derive well, groundwater or water-right analysis — it reads the sibling platform's output and links to the full report for the underlying records and methodology.

Montana Fire Report

Summarised here. The underlying DNRC statewide fuel and burn-probability modelling was finalised in December 2019 from LANDFIRE Remap 2016, so post-2019 fire, logging and fuel treatment is not reflected. The full Fire Report carries that caveat in detail.