Many regions in the United States are defined in law or regulations by the federal government.
Census Bureau-designated regions and divisions
U.S. Census Bureau Regions and Divisions.
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.
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
East Coast: Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New Jersey, Delaware, Maryland, Virginia, North Carolina, South Carolina, Georgia, Florida; along with counties in New York east of, north of and including Cayuga, Tompkins, and Chemung; and counties in Pennsylvania east of and including Bradford, Sullivan, Columbia, Montour, Northumberland, Dauphin and York.
Appalachian No. 1: West Virginia along with counties of Pennsylvania and New York State not mentioned above.
Texas Gulf Coast: The Texan counties of Newton, Orange, Jefferson, Jasper, Tyler, Hardin, Liberty, Chambers, Polk, San Jacinto, Montgomery, Harris, Galveston, Waller, Fort Bend, Brazoria, Wharton, Matagorda, Jackson, Victoria, Calhoun, Refugio, Aransas, San Patricio, Nueces, Kleberg, Kenedy, Willacy and Cameron
Texas Inland: Texan counties not mentioned above.
Louisiana Gulf Coast: Parishes of Louisiana south of, and including Vernon, Rapides, Avoyelles, Pointe Coupee, West Feliciana, East Feliciana, Saint Helena, Tangipahoa and Washington; along with Pearl River, Stone, George, Hancock, Harrison, and Jackson County of Mississippi; and Alabama's Mobile and Baldwin County.
North Louisiana-Arkansas: Arkansas and parts of Louisiana, Mississippi and Alabama not mentioned above.
PADD I can also be subdivided into 3 Subdistricts:
Sub-PAD 1A: New England (Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, Vermont)
Sub-PAD 1B: Central Atlantic (Delaware, Maryland, New Jersey, New York, Pennsylvania, District of Columbia)
Sub-PAD 1C: Lower Atlantic (Florida, Georgia, North Carolina, South Carolina, Virginia, West Virginia)
PADD system was established in World War II and therefore don't accurately reflect current trends. The EIA has updated the PADD system with a complimentary set of regions to reflect this and will change it to suite current needs. (Note: Region 9 includes countries not part of the USA but is included for the sake of completion since it contains Puerto Rico)
Region 1: PADD I
Region 2: PADD II "Inland" (States of North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, Missouri, Iowa, Tennessee and Kentucky)
Region 3: PADD II "Lakes" (States of Minnesota, Wisconsin, Illinois, Michigan, Indiana and Ohio)
Region 4: PADD III "Gulf" (Refining districts of Texas Gulf Coast and Louisiana Gulf Coast)
Region 5: PADD III "Inland" (Refining districts of Texas Inland, New Mexico and North Louisiana-Arkansas)
Region 6: PADD IV
Region 7: PADD V "California" (State of California)
Region 8: PADD V "Other" (States of Alaska, Arizona, Hawaii, Nevada, Oregon and Washington)
In Connecticut, there are 14 official regions, each with a regional government that serves for the absence of county government in Connecticut. There are also a fair number of unofficial regions in Connecticut with no regional government.