Go to the Wikipedia page for the county you're interested in and scroll to the list of communities. The page for Warren County, Indiana, for example, lists the following "extinct places:"
- Chatterton (in Adams Township)
- Baltimore (in Mounds Township)
- Brisco and Point Pleasant (in Pine Township)
- Locust Grove and Walnut Grove (in Prairie Township)
- Chesapeake, Dresser, and Sloan (in Steuben Township)
- Warrenton and Kickapoo (in Warren Township)