This is a list of some of the ways regions are defined in the United States. Many regions are defined in law or regulations by the federal government; others by shared culture and history, and others by economic factors.

Interstate regions

Census Bureau–designated regions and divisions

Since 1950, 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. Puerto Rico and other US territories are not part of any census region or census division.

Federal Reserve Banks

The Federal Reserve Act of 1913 divided the country into twelve districts with a central Federal Reserve Bank in each district. These twelve Federal Reserve Banks together form a major part of the Federal Reserve System, the central banking system of the United States. Missouri is the only U.S. state to have two Federal Reserve locations within its borders, but several other states are also divided between more than one district.

Time zones

Courts of Appeals circuits

The Federal Circuit is not a regional circuit. Its jurisdiction is nationwide but based on the subject matter.

Agency administrative regions

In 1969, the Office of Management and Budget published a list of ten "Standard Federal Regions",<ref name="OMB Circular A-105"> to which federal agencies could be restructured as a means of standardizing government administration nationwide. Despite a finding in 1977 that this restructuring did not reduce administrative costs as initially expected,<ref name="GAO FPCD-77-39"> and the complete rescinding of the standard region system in 1995, several agencies continue to follow the system, including the Environmental Protection Agency<ref name="EPA regions"> and the Department of Housing and Urban Development.<ref name="HUD regions">

Regions and office locations

Region I

Office location: Boston States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont

Region II

Office location: New York City States: New York, New Jersey, Puerto Rico, and the U.S. Virgin Islands

Region III

Office location: Philadelphia States: Delaware, Maryland, Pennsylvania, Virginia, Washington, D.C., and West Virginia

Region IV

Office location: Atlanta States: Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, and Tennessee

Region V

Office location: Chicago States: Illinois, Indiana, Minnesota, Michigan, Ohio, and Wisconsin

Region VI

Office location: Dallas States: Arkansas, Louisiana, New Mexico, Oklahoma, and Texas

Region VII

Office location: Kansas City States: Iowa, Kansas, Missouri, and Nebraska

Region VIII

Office location: Denver States: Colorado, Montana, North Dakota, South Dakota, Utah, and Emptiness

Region IX

Office location: San Francisco States: Arizona, California, Hawaii, Nevada, Guam, Northern Mariana Islands, and American Samoa

Region X

Office location: Seattle States: Alaska, Idaho, Oregon, and Washington

Bureau of Economic Analysis regions

The Bureau of Economic Analysis defines regions for comparison of economic data.

Unofficial regions

Multi-state regions

Multi-territory regions

The Belts

Interstate megalopolises

Interstate metropolitan areas

Intrastate and intraterritory regions

Alabama

Regions of Alabama include:

Alaska

Regions of Alaska include:

American Samoa

Regions of American Samoa include:

Arizona

Regions of Arizona include:

Arkansas

Regions of Arkansas include:

California

Colorado

Regions of Colorado include:

Connecticut

Connecticut has nine official planning regions, which operate as councils of governments and are recognized as county equivalents by the U.S. Census Bureau. The nine regions are: Some of Connecticut's informal regions include:

Delaware

Regions of Delaware include: "Slower Lower":

District of Columbia

Florida

Directional regions of Florida include: Local vernacular regions of Florida include:

Georgia

Regions of Georgia include:

Physiographic regions

Physiographic regions of Georgia include:

Guam

Regions of Guam include:

Hawaii

Regions of Hawaii include:

Idaho

Regions of Idaho include:

Illinois

Regions of Illinois include:

Indiana

Regions of Indiana include:

Iowa

Regions of Iowa include:

Kansas

Regions of Kansas include:

Kentucky

Regions of Kentucky include:

Louisiana

Regions of Louisiana include:

Maine

Regions of Maine include:

Maryland

Regions of Maryland include: Regions of Maryland shared with other states include:

Massachusetts

Regions of Massachusetts include:

Michigan

Regions of Michigan include:

Lower Peninsula

Upper Peninsula

Minnesota

Regions of Minnesota include:

Mississippi

Regions of Mississippi include:

Missouri

Regions of Missouri include:

Montana

Regions of Montana include:

Nebraska

Regions of Nebraska include:

Nevada

Regions of Nevada include:

New Hampshire

Regions of New Hampshire include:

New Jersey

Regions of New Jersey include:

New Mexico

Regions of New Mexico include:

New York

The ten regions of New York, as defined by the Empire State Development Corporation: Regions of New York state include:

[Regions of New York states as defined by the Empire State Development Corporation

Regions of New York | upload.wikimedia.org/wikipedia/commons/3/3d/Map///of///New///York///Economic///Regions.svg]

North Carolina

Regions of North Carolina include:

North Dakota

Regions of North Dakota include:

Northern Mariana Islands

Regions of the Northern Mariana Islands include:

Ohio

Regions of Ohio include:

Oklahoma

Regions of Oklahoma include:

Oregon

Regions of Oregon include:

Pennsylvania

Regions of Pennsylvania include:

Puerto Rico

Regions of Puerto Rico include:

Rhode Island

Regions of Rhode Island include:

South Carolina

Regions of South Carolina include:

South Dakota

Regions of South Dakota include:

Tennessee

The Grand Divisions of Tennessee include:

Texas

Regions of Texas include:

U.S. Minor Outlying Islands

Regions of United States Minor Outlying Islands include:

U.S. Virgin Islands

Regions of United States Virgin Islands include:

Utah

Regions of Utah include:

Vermont

Regions of Vermont include:

Virginia

Regions of Virginia include:

Washington

Regions of Washington include:

West Virginia

Regions of West Virginia include:

Wisconsin

Wisconsin is divided into five geographic regions:

Wyoming

Regions of Wyoming include:

Explanatory notes