Other sources for historical data?

Hi all,

I know that OpenStreetMap doesn’t have historical data, but I am designing a research project and including the change in roads over time would be useful.

If anyone knows of any data sources that could be useful (lower 48 of USA, back to 1960s preferred) please let me know. I’ve poked around a bit and this doesn’t seem feasible, but I am posting here just in case.