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. The most common tri-state area is the greater New York City area, made up of New York, New Jersey, and Connecticut. 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.