The United States Census Bureau defines four statistical regions, with nine divisions. The Census Bureau region definition is “widely used … for data collection and analysis,” and is the most commonly used classification system.
Many regions in the United States are defined in law or regulations by the federal government.
Region 1: Northeast
Division 1: New England (Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont)
Division 2: Mid-Atlantic (Delaware, New Jersey, New York, and Pennsylvania)
Region 2: Midwest (Prior to June 1984, the Midwest Region was designated as the North Central Region.)
Division 3: East North Central (Illinois, Indiana, Michigan, Ohio, and Wisconsin)
Division 4: West North Central (Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, and South Dakota)
Region 3: South
Division 5: South Atlantic (Florida, Georgia, Maryland, North Carolina, South Carolina, Virginia, District of Columbia, and West Virginia)
Division 6: East South Central (Alabama, Kentucky, Mississippi, and Tennessee)
Division 7: West South Central (Arkansas, Louisiana, Oklahoma, and Texas)
Region 4: West
Division 8: Mountain (Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Utah, and Wyoming)
Division 9: Pacific (Alaska, California, Hawaii, Oregon, and Washington)
Puerto Rico and other US territories are not part of any census region or census division as of 2015.
STANDARD FEDERAL REGIONS
The ten standard federal regions were established by OMB (Office of Management and Budget) Circular A-105, “Standard Federal Regions,” in April, 1974, and required for all executive agencies. In recent years, some agencies have tailored their field structures to meet program needs and facilitate interaction with local, state and regional counterparts. However, the OMB must still approve any departures.
Region I: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, Vermont
Region II: New Jersey, New York, Puerto Rico, US Virgin Islands
Region III: Delaware, District of Columbia, Maryland, Pennsylvania, Virginia, West Virginia
Region IV: Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, Tennessee
Region V: Illinois, Indiana, Michigan, Minnesota, Ohio, Wisconsin
Region VI: Arkansas, Louisiana, New Mexico, Oklahoma, Texas
Region VII: Iowa, Kansas, Missouri, Nebraska
Region VIII: Colorado, Montana, North Dakota, South Dakota, Utah, Wyoming
Region IX: Arizona, California, Hawaii, Nevada, American Samoa, Guam, Northern Mariana Islands, Trust Territory of the Pacific Islands
Region X: Alaska, Idaho, Oregon, Washington