The 2010 Guide to State and Local Census Geography is now available. This Product is an update of the book by the same name that the Census Bureau produced in collaboration with the Association of Public Data Users (APDU) following the 1990 Census. (There was no similar product for 2000.) The 2010 web version offers similar content as the 1990 print version, but also provides links to lists of geographic entities within each state.
This guide provides a nice summary of each state’s geographic structure and some highlights about the state’s geographic history and current geography. Here's New York’s information.