Combined statistical area (CSA) is a United States Office of Management and Budget (OMB) term for a combination of adjacent metropolitan (MSA) and micropolitan statistical areas (μSA) across the 50 U.S. states and the territory of Puerto Rico that can demonstrate economic or social linkage. CSAs were first designated in 2003. OMB defines a CSA by various combinations of adjacent metropolitan and micropolitan areas with economic ties measured by commuting patterns. CSAs retain their own designations as metropolitan or micropolitan statistical areas in their respective larger combined statistical areas.
The primary distinguishing factor between a CSA and an MSA/μSA is that the social and economic ties between the individual MSAs/μSAs within a CSA are at lower levels than those between the counties within an MSA. CSAs represent multiple metropolitan or micropolitan areas that have an employment interchange of at least 15% (% commuting from A to B plus % commuting from B to A). CSAs often represent regions with overlapping labor and media markets.
As of 2023, there are 184 combined statistical areas across the United States, including three in the territory of Puerto Rico.__TOC__
United States
This table lists the 181 combined statistical areas (CSAs) of the United States with the following information: The CSA rank by population as of July 1, 2025, as estimated by the U.S. Census Bureau The CSA name as designated by the United States Office of Management and Budget The CSA population as of July 1, 2025, as estimated by the United States Census Bureau The CSA population as of April 1, 2020, as enumerated by the 2020 United States census The percent CSA population change from April 1, 2020, to July 1, 2025 The core-based statistical areas (CBSAs) that constitute the CSA Metropolitan statistical areas that are not also combined with other MSAs or CBSAs are not listed below.