DSDR KB:

For single year data (2007), there is still a population threshold of 65,000. This is based on the Census Bureau estimate of the population on July 1, 2007. The following is a spreadsheet that shows each state's population size for 2000 (census) and the estimates for 2005, 2006, and 2007. The table is sorted by state and within state, by population size for 2007:

Counties

Incorporated_Places

The ACS website has maps for each state:

http://www.census.gov/acs/www/Products/usersguide/acs2007referencemaps.htm

In addition, one can get a list of the counties available for single states by choosing the state in the upper left corner of the interface to the ACS 2007 Product Details:

http://www.census.gov/acs/www/Products/users_guide/