The [http://www.uwyo.edu/ University of Wyoming] in Laramie has a fine collection of maps and atlases including the [http://libguides.uwyo.edu/content.php?pid=285920&sid=2353188 Hebard Historic Map Collection] which includes online images. The [https://sites.google.com/a/wyo.gov/seo/ Wyoming State Engineer's Office] at Cheyenne has a large library of [https://sites.google.com/a/wyo.gov/seo/documents-data/maps-and-spatial-data technical maps].
The [https://familysearch.org/locations/saltlakecity-library Family History Library] has a few maps of [[WyomingGenealogy|Wyoming]]. These show trails, roads, forts, migration routes, and other features. Atlases that describe Wyoming's progression from Indian lands through various territorial designations are on Family History Library film {{FHL|002083|film|disp=002083}}.
[http://ftp2.census.gov/geo/maps/general_ref/us_base/stco2003/stco2003.pdf United States Census Bureau State and County Map]. This map will allow you to zoom in on any state or county in the United States and read the names of all of the neighboring counties.