Guides to historical place names in Delaware include:
Heck, L. W. Delaware Place Names. Washington, DC: U.S. Government Printing Office, 1966.
U.S. Geological Survey. National Gazetteer of the United States: Delaware 1983. Washington, DC: Government Printing Office, 1984. This book has names of places, a map of Delaware "hundreds" (these are county subdivisions similar to townships) and an alphabetical list of geographical sites, such as cemeteries and churches that are named on topographical survey maps.