Data Credits
Last updated: July 10, 2026
Trailmonger maps are built on open and public-domain data published by U.S. federal and state agencies and open-data communities. We are grateful to the people who collect, maintain, and publish these datasets. Third-party data remains subject to its publishers' terms.
Base Map & Trails
- OpenStreetMap contributors — Trails, roads, points of interest, and base map features. Open Database License (ODbL) 1.0.
- Esri World Imagery — Satellite and aerial basemap imagery. Esri Master Agreement terms.
Elevation & Terrain
- USGS 3D Elevation Program (3DEP) — Elevation models, hillshade, and contour data. Public domain.
Water & Marine
- USGS 3D Hydrography Program (3DHP) — Rivers, streams, and hydrography. Public domain.
- NOAA ENC Direct to GIS — Depth areas, depth contours, and soundings for coastal waters and the Great Lakes. Public domain — not for navigation.
- NOAA National Bathymetric Source (BlueTopo) — Compiled bathymetry for U.S. waters. Public domain — not for navigation.
- NOAA CO-OPS — Tide station locations and tide predictions. Public domain — predictions, not for navigation.
- NOAA National Centers for Environmental Information (NCEI) — Great Lakes bathymetry grids (Superior, Huron, Erie, Ontario depth bands and contours). Public domain — not for navigation.
- Michigan Department of Natural Resources — Inland lake depth contours, Lake Michigan bathymetric contours, and waterbody outlines. State of Michigan open data (provided as-is).
- Minnesota Department of Natural Resources — Lake bathymetric contours and lake outlines. Minnesota Geospatial Commons open data.
- Washington State Department of Ecology — Lake bathymetry contour lines and depth bands. Washington State open data.
- OpenSeaMap contributors — Supplemental nautical overlay outside surveyed coverage. CC BY-SA 2.0.
Boundaries & Public Lands
- USGS Protected Areas Database (PAD-US) — Federal, state, local, and tribal public land boundaries. Public domain.
- NOAA Marine Protected Areas Inventory — Marine protected area boundaries and classifications. Public domain — not for regulatory purposes.
- U.S. Census Bureau TIGER/Line — State, county, and tribal statistical boundaries. Public domain.
Weather & Conditions
- NOAA National Weather Service — Forecasts, radar imagery, and weather alerts. Public domain.
- USGS Water Data — Streamflow gauges and river conditions. Public domain.
Navigation Disclaimer
Depth, tide, and marine boundary information in Trailmonger is compiled from public survey data and is provided for planning and general awareness only. It is not suitable for navigation. Consult official charts and regulations before operating on the water.