RUCA version 2.0 was created based on 2000 Census commuting data and 2004 ZIP codes. There are 41,928 cases in this file. This file became available in July 2005. Go to download to retrieve the ZIP code-based data. Go to general methods for information regarding code development.
The Census tract RUCA codes are only kept on the U.S. Department of Agriculture Economic Research Service's web site, and the ZIP code versions are only kept on this web site. This ensures that there is only one source of each to eliminate the possibilities of update errors and timing lags. The Census Tract RUCA codes are available here.