“John C. H. Grabill sent one hundred and eighty eight photographs to the Library of Congress between the years 1887 and 1892. This collection is considered the premier collection of western frontier photography in the United States today. Known for their gritty realism, these sepia-toned windows to the past capture the American West in the midst of settlement. The well-crafted images evoke a definite sense of place and time that allow the viewer to peer into a world that otherwise survives only in our imaginations, and the stuff of legends.”

-Margaret McGuire, 2004. From Digital Picture Printing & Framing

Grabill’s photographs are gritty, realistic, and immediate. The entire collection can be found at the Library of Congress. Several sizes are available for download, including hi-res Tiffs.
I used one of his shots of Deadwood, Dakota Terr. to make my banner and another shot of his is my current wallpaper.
Here’s a few of my favorites:

There are many more her and they are wonderful inspiration for your Western game.

For my last Deadlands game I detailed the fictional town of Melody Colorado. I played around with some of the details, but it partially replaces Walsenburg Colorado, the county seat of Huerfano County. I choose Huerfano Co., despite never having been there, because it was along a cattle trail, had good mining and farming, and was close to Texas, New Mexico, and Arizona. It was also one of the original 17 counties of Colorado which I felt increased my chances of finding historical information online.

I was able to get some great history about Huerfano county that inspired and informed my game. For example both “The History of the Georgia Colony” and “Hispanic Heritage in Huerfano County, Colorado” from this excellent page: Huerfano County Resources.

Here’s what I ended up with:
A large map of Melody - 1.9 Mb jpeg, 3400px × 4400px
A players map of Melody - 580 kb PDF
Melody People and Places.

My point for all of this is that you should always check to actual history of the region your game is set in, you never know what cool stories you’ll turn up. And, if nothing else, you’ll get some good local flavor.

The Amon Carter Museum has a web feature called “Texas Bird’s-Eye Views” that features some really nice maps of various Texas towns from 1871-1892. While they are behind a Flash-based map viewer at the website, many of them are also on Wikimedia Commons.

After the Civil War there was an explosion in panoramic or bird’s-eye view city maps. The techniques and technology were sufficiently advanced to produce beautiful works of art. There is a detailed article on Bird’s Eye View map phenomenon at the Anon Carter site.

Below are some samples:
Austin, 1873.
Austin, 1887.
Eagle Pass, 1887.
Fort Worth, 1876.
Fort Worth, 1886.
Fort Worth, 1891.
McKinney, 1876.

All told there are 60 maps on the Amon Carter site, and many are also available on Wikimedia Commons and these are only for Texas towns. I’m sure with some digging we can find more primary source maps of Old West towns, in fact you can count on it.