Historical Aerial Maps

USDA-FSA
Aerial Photography Field Office
2222 W 2300 S
Salt Lake City, UT
84119-2020
801-844-2900
www.apfo.usda.gov

If you are like me you will need to call them to find out what's available, they are very helpful. They have stuff going back to the 40's, but not for everywhere. I got a 1958 map this summer. I bought a print and also a scan.

click the little clock in Google Earth, a timeline will come up with a slider that you can use to "go back in time"

I would start with the USGS link below:

http://eros.usgs.gov/

And then the USDA link below:

http://www.nrcs.usda.gov/wps/portal/nrcs/main/national/home

Loyal

USGS Earth Explorer is one source I use. It is somewhat user friendly:

http://edcsns17.cr.usgs.gov/NewEarthExplorer/