Maps of the Nevada area for 1862, 1878, 1884, and 1917 are available at the Family History Library (See FHL film 002083.) The Family History Library also has a small collection of county and city maps.
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.
More recent maps can be found at:
Find additional maps by using a search engine and searching for terms such as "Nevada" (or your specific location) and "Maps."
Printable maps are also available from the National Atlas of the United States: