[paxswill]

If you're referring to maps produced by the US government, they are in the public domain. Early on it sounds like there wasn't an easy way to transfer "raw" map data around (hence the tracing), but it's pretty easy now to access official maps in full resolution:

* US Geological Survey: https://www.usgs.gov/core-science-systems/ngp/tnm-delivery

* National Park Service: https://mapservices.nps.gov/arcgis/rest/services

* US Forest Service: https://www.fs.usda.gov/visit/maps (the API access is further down that page).

Those linked above typically available through a standard API (Tile Map Service), as well as ESRI's moderately well documented REST API for accessing shapefiles and features. My one complaint about this data is how the USFS manages their data. In that case it seems each service region defines how data should be made available, so you have a pile of different methods for accessing things like road/trail features, or points of interest (in many cases, it comes down to "fetch this pile of ZIP files").