This is a massive collection of historical maps and related images. It is very well organized and easily searched using the LUNA Imaging software. Information here:

https://en.wikipedia.org/wiki/David_Rumsey_Historical_Map_Collection

Collection here:

http://www.davidrumsey.com/

Copyright summary:

"Images may be reproduced or transmitted, but not for commercial use. For commercial use or commercial republication, contact mailto:carto@davidrumsey.com This work is licensed under a Creative Commons License."

I'm working on an animation project set in San Francisco in the 1890's, and found an amazing collection of nearly 200 street view drawings from 1895:

http://tinyurl.com/j4cds4r

Check it out.