You can get these direct from USGS in KMZ, GeoTIFF, GeoPDF, and JPEG format. And mobile apps like Topo Reader and Avenza Maps for iOS will let you load them fo

You can get these direct from USGS in KMZ, GeoTIFF, GeoPDF, and JPEG format. And mobile apps like Topo Reader and Avenza Maps for iOS will let you load them for live referencing. I just “discovered” this yesterday, by chance. https://www.usgs.gov/programs/national-geospatial-program/historical-topographic-maps-preserving-past https://www.usgs.gov/programs/national-geospatial-program/hi... https://ngmdb.usgs.gov/topoview/viewer/#4/39.98/-99.98 https://ngmdb.usgs.gov/topoview/viewer/#4/39.98/-99.98