Ohio

Postcards of Akron.   Although this site is map-less, it does contain a substantial collection of excellent historical postcard images.  Included are downtown Akron; churches, parks, bridges, and industry; Wadsworth; and Great Lakes ships and harbors.  From the University of Akron Center for Policy Studies.  [ccr]
http://www3.uakron.edu/majuro/Postcards/

Historic Old West End of Toledo.   Historic images of this "Largest neighborhood of late Victorian, Edwardian, and Arts and Crafts homes east of the Mississippi."  Also includes images of downtown Toledo and other specific themes.  Little text, no map, but great images.  Created by the Old West End Association.  [ccr]
http://www.oldwestendtoledo.com/index.html 

Marietta.   Take a virtual tour of this historic Ohio River town.  There are currently 53 stops on the tour. Each stop has historical information along with pictures of the area. [tdh]
http://mariettaohio.info/media/tour/index.php

Newburgh and South Shore Railway. A clickable-map leads to some fantastic historic photos of this railroad, from an unpublished collection at the Cleveland State Library.  A link leads to all 99 photos from the ca. 1920 collection.  [ccr]
http://web.ulib.csuohio.edu/SpecColl/nssbk/nssmap2.html

Covered bridges.  Cascading maps lead to multiple images of dozens of covered bridges all over the state. 
http://www.dot.state.oh.us/se/coveredbridges/