US Federal Public Lands — ForeFlight Map Overlays

Source & methodology · Files generated October 2026

Source data

These overlays are derived from the USGS Protected Areas Database of the United States (PAD-US), version 4.1, a public-domain compilation of the nation’s protected-area and public-land boundaries published by the U.S. Geological Survey. Two PAD-US components were used:

• Fee ownership layer — federal lands by managing agency.
• Combined designation layer — congressionally designated Wilderness areas.

What’s included

One KMZ file per state, each with toggleable layers:

• BLM — Bureau of Land Management
• USFS — USDA Forest Service
• NPS — National Park Service
• FWS — US Fish & Wildlife Service
• USACE — Army Corps of Engineers
• USBR — Bureau of Reclamation
• TVA — Tennessee Valley Authority
• Other Federal — remaining federal managing agencies
• Wilderness — designated Wilderness areas (helicopter landings generally prohibited; AIM 7-5-6 requests ≥2,000 ft AGL)

Excluded: Department of Defense / military lands, Department of Energy lands, and agricultural research lands, which are not public-use lands for these purposes. State, county, tribal, and private lands are not shown — everything not colored is not necessarily private or landable; it is simply not in this dataset.

How the layers were generated

• For each state, all federal fee units for the eight agencies above were extracted, simplified, and merged into one polygon per agency per state.
• Boundaries were simplified with a 0.0005° (~55 m / 180 ft) tolerance to keep the files small enough for ForeFlight to render.
• Fragments smaller than about one hectare and tiny holes were removed; invalid geometries were repaired; oversized features were subdivided.
• Coordinates are stored at 5 decimal places (~1 m precision).
• Output: KMZ (compressed KML), one file per state, compatible with ForeFlight’s Custom Map Layers.

Accuracy and limitations

• Boundaries are approximate. Measured deviation of the simplified boundaries versus the PAD-US source is up to roughly 300 feet; treat every boundary as approximate within a few hundred feet.
• PAD-US itself is a compilation — agencies submit generalized versions of their internal data, and vertex spacing in the source is commonly 70–160 m. It is not a legal boundary survey, and finer detail than the source cannot be recovered by any processing.
• Land status changes: units are acquired, exchanged, or re-designated, and PAD-US is updated periodically. These files reflect PAD-US v4.1 as of October 2026.
• Simplification replaces curves with straight segments; zoomed in close, boundaries will look angular. That is expected and does not indicate an error beyond the stated tolerance.