The following books include maps and historical information for Nebraska:
The Official State Atlas of Nebraska. 1885. Reprint. Evansville, Indiana: Unigraphic, 1976. (Family History Library book Q 978.2 E3e 1976; film 1036154 item 12.)
Nimmo, Sylvia. Maps Showing County Boundaries of Nebraska, 1854-1925. Papillion, Nebraska: [S.n.], 1978. (Family History Library book 978.2 E7m.)
The best collection of maps helpful for genealogical research is at the Nebraska State Historical Society. Map collections are available on interlibrary loan through the University of Nebraska at Lincoln and at Omaha. Kearny State College also has a good map collection.
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.
Printable maps are also available from the National Atlas of the United States -- http://nationalatlas.gov/printable.html