This rule makes final the Community Development Block Grant (CDBG) program regulations that replaced the obsolete term "central city" with a new term "principal city" in the definition of "metropolitan city" and other CDBG regulations referencing "central city." The revisions were necessary because of the recent changes to the Office of Management and Budget's (OMB) Standards for Defining Metropolitan and Micropolitan Statistical Areas (MSAs) and the announcement in 2003 of new definitions for those areas using Census 2000 data. The rule also updated the affected CDBG program regulations so that the terminology used by HUD is consistent with OMB standards and the purposes of the Housing and Community Development Act of 1974. This rule follows an interim rule that was published in the Federal Register December 12, 2003. One comment was received in response to the interim rule. After careful consideration of the comment received in response to the interim rule, this rule makes final without change the interim rule published on December 12, 2003.