The USGS maintains a web page that can be used to search a database of place names, both for the United States and places around the world. The web page is one part of the Geographic Name Information System (GNIS). The USGS also maintains a database for the GNIS. You can download the data from this database for all 50 of the states in the United States as a single zip file, or for just a single state.
The home page for the GNIS is here.
The web page that lets you search for place names is here.
The wikipedia page for the GNIS is here.
You can even use the site to propose a new place name, which is pretty cool.
I wonder if other countries maintain a database of place names like the GNIS.
The Sunburned Surveyor