Tri-state area is an informal term in the eastern United States for any of the regions associated with a particular metropolis that lies across the three states. Some tri-state areas involve a state boundary tripoint.
Of the 62 points in the United States where three states meet, 35 are on land and 27 are in the water.
Examples of these tri-state areas include:
- The Philadelphia metropolitan area, covering parts of Pennsylvania, New Jersey, and Delaware
- The Greater Boston area covering parts of Massachusetts, Rhode Island, and New Hampshire
- The Pittsburgh area covering Pennsylvania, Ohio, and West Virginia
- The Minisink Valley region covering Orange County, New York; Sussex County, New Jersey; and Pike County, Pennsylvania
- The Cincinnati metro area including Ohio, Kentucky, and Indiana
- The Chicago tri-state area (Chicagoland) covering Illinois, Indiana, and Wisconsin
- The Greater Memphis area (Mid-South) including Tennessee, Mississippi, and Arkansas
- The Dubuque, Iowa area includes Illinois and Wisconsin
- The La Crosse, Wisconsin area also includes La Crescent, Hokah, and Brownsville in Minnesota and New Albin and Lansing in Iowa.
- The Chattanooga tri-state area includes parts of Tennessee, Alabama, and Georgia
- The District of Columbia area is known as the D.M.V. - D.C., Maryland, and Virginia (even though the District of Columbia is not a state)
- The Joplin District is a region of Oklahoma, Kansas, and Missouri known for mining lead and zinc
- The Winegrass Region includes parts of Alabama, Georgia, and Florida
- The Sioux City metro area covers parts of Iowa, Nebraska, and South Dakota
- Litchfield County, Connecticut; Berkshire County, Massachusetts; and eastern Dutchess County, New York are referred to as the “tri-state area” or the “tri-corners”
- The Quincy, Illinois tri-state area includes Missouri and Iowa
- The Illinois-Indiana-Kentucky tri-state area around Evansville, Indiana
- The Huntington-Ashland metropolitan area includes towns in Kentucky, Ohio, and West Virginia.
Some tri-state areas can be met on water. Examples of these include:
- Delaware, New Jersey, and Pennsylvania meet at the Delaware River in the Philadelphia metro area.
- Illinois, Indiana, and Michigan, which converge at Lake Michigan. This is also known as the Indiana Dunes or the Michigan Dunes area.
- Alabama, Mississippi, and Tennessee meet at the Tennessee River
- Connecticut, New York, and Rhode Island meet at the Long Island Sound
- Illinois, Indiana, and Kentucky meet at two points: the Wabash River and the Ohio River
- Illinois, Kentucky, and Missouri meet at two points: the Mississippi River and Ohio River
- Maryland, Virginia, and West Virginia at the Potomac River
- Ohio, Pennsylvania, and West Virginia at the Ohio River
- Michigan, Minnesota, and Wisconsin at Lake Superior
In addition to tri-state areas with tri-points, some regions of three states that are “tri-state areas” do not have a single meeting point. These are:
- The Gulf Coast Region: Alabama, Florida, and Mississippi
- The New York metropolitan area: Connecticut, New Jersey, and New York
- The Wilmington, Delaware metro area: Delaware, Maryland, and New Jersey
- Delmarva Peninsula: Delaware, Maryland, and Virginia
- The Spokane, Washington area (connected by Interstate 90): Idaho, Montana, Washington
- Chicago metro area; Illinois, Montana, Washington
- The Liberal, Kansas area: Kansas, Oklahoma, Texas
- Erie metro area, also called the Niagara Frontier and North Coast: New York, Pennsylvania, Ohio
- The metro areas of Spartanburg, South Carolina; Asheville, North Carolina; and Johnson City and Kingsport Tennessee are connected along Interstate 26.
- Northern New England: Vermont, New Hampshire, and Maine
- West Virginia, Virginia, and North Carolina are connected at an intersection of Interstate 77, connecting Charleston, West Virginia; Charlotte, North Carolina; and Wytheville Virginia.