Additional detail about the project is also available by visiting the About pages for individual states.
Hamlin, Homer. Map showing territory annexed to the city of Los Angeles, California. [Los Angeles, Calif.:] City Engineer, 1916. https://hdl.loc.gov/loc.gmd/g4364l.ct001800.
Thanks to The Newberry, in Chicago, Ill., for permission to use Atlas of Historical County Boundaries data in this resource, which will be incorporated in a future version.
Like many projects of this scale, the vast amount of knowledge to be uncovered often exceeds the resources available. The following priorities generally decide what information is included:
- Geohistory events for incorporated places, such as boroughs, cities, and villages, are prioritized over those for townships and other county subdivisions.
- Incorporations, name changes, consolidations, mergers, disincorporations, and substantial government form change events are prioritized over annexations. In turn, annexations are prioritized over minor boundary adjustments and disputed boundary determinations.
- Modern geohistory events, particularly since 1900, are prioritized over older geohistory events, which are often chronicled in preexisting county histories.
- Identifying geohistory events and cataloging primary source citations is prioritized over GIS efforts.