The free maps can be integrated with GPS devices or mobile apps, providing real-time navigation in the field. | Credit: The ...

USGS topoView The maps can be downloaded in various formats, including KMZ for viewing in Google Earth. A topographic map of Fort Smith, Arkansas, from 1887.

Further information about how to download and use US Topo, currently available coverage, and the timetable for production of US Topo maps can be found online at: nationalmap.usgs.gov/ustopo .

It just got way, way easier to search and browse the US Geological Survey’s collection of historical topographic maps, thanks to a new online map viewer. These maps—more than 178,000 of them ...

More specifically the 310, 510, 610 and 710 models. If you like the sound of the full color USGS topographic maps, then they are available on a subscription basis for $30 a year.