the Office of Management and Budget (OMB), United States, defines 929 Core-Based Statistical Areas (CBSAs)

The OMB defines statistical areas for the metropolitan and micropolitan areas of the United States and Puerto Rico. Most recently on February 28, 2013, the OMB defined 1098 statistical areas for the United States and Puerto Rico. These 1098 statistical areas comprise 929 Core Based Statistical Areas (CBSAs) and 169 Combined Statistical Areas (CSAs). The 929 Core Based Statistical Areas are divided into 388 Metropolitan Statistical Areas (MSAs – 381 for the U.S. and seven for Puerto Rico) and 541 Micropolitan Statistical Areas (µSAs – 536 for the U.S. and five for Puerto Rico). The 169 Combined Statistical Areas (166 for the U.S. and three for Puerto Rico) each comprise two or more adjacent Core Based Statistical Areas.

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