The Evans Map Room of the Dartmouth College Library, located in Berry Library on the 2nd level next to the Jones Media Center contains over 190,000 maps, 1,000 atlases, and 15 globes. Among its many resources are many historical atlases, gazetteers, and sheet maps of places throughout the world with special emphasis upon New Hampshire, Vermont, and communities in the Upper Connecticut River Valley.
Maps published in a specific year a genealogist has interest in is worth its weight in gold. The Evans Map Room has maps drawn at various time periods in United States history.
However, we also have software which allows a user to create a historical county map of any of the contiguous states. You can pick a year and see a map of the state as it looked during that year. This is particular helpful because counties changed their boundaries and their names. You can also plot cities and towns to make their importance more relevant to readers of your genealogies.
Atlases produced by Frederick W. Beers are famous for their detailed local history information. All of the Vermont counties, as well as other states, were mapped by Mr. Beers, et. al.
(Text and resources taken from the print edition of: Jaccaud, Robert D, comp. Passages to Family History: A Guide to Genealogical Research in the Dartmouth College Library. Rev. ed. Hanover: Dartmouth College Library, 1994).