Because of its unique history, many of the boundaries of
political divisions of the United States were artificially constructed (rather than being permitted to evolve and drawn using natural features of the landscape). Therefore, many
U.S. states have straight lines as boundaries, especially in the
West. That said, there are a number of states, particular in the
Midwest and
North with at least partial river borders.
- Big Sioux River: South Dakota, Iowa
- Bois de Sioux River: South Dakota, Minnesota, North Dakota
- Catawba River: North Carolina, South Carolina
- Chattahoochee River: Alabama, Georgia
- Chattooga River: Georgia, South Carolina
- Connecticut River: Vermont, New Hampshire, Quebec
- Colorado River: Arizona, Nevada, California
- Columbia River: Washington, Oregon
- Delaware River: New York, Pennsylvania, New Jersey, Delaware
- Des Moines River: Iowa, Missouri
- Detroit River: Michigan, Ontario
- Great Miami River (mouth only): Ohio, Indiana
- Kentucky River: Kentucky, Tennessee
- Menominee River: Michigan, Wisconsin
- Mississippi River: Minnesota, Wisconsin, Iowa, Illinois, Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and Louisiana
- Missouri River: South Dakota, Nebraska, Iowa, Missouri, Kansas
- Montreal River: Michigan (Upper Peninsula), Wisconsin
- Monument Creek: Maine, New Brunswick
- Niagara River: New York, Ontario
- Ohio River: Illinois, Indiana, Ohio, Kentucky, West Virginia
- Pawcatuck River: Connecticut, Rhode Island
- Piscataqua River: Maine, New Hampshire
- Pearl River: Mississippi, Lousiana
- Perdido River: Florida, Alabama
- Pigeon River: Minnesota, Ontario
- Pocomoke River: Maryland, Virginia
- Potomac River: District of Columbia, West Virginia, Virginia, Maryland
- Poultney River: Vermont, New York
- Rainy River: Minnesota, Ontario, Canada
- Red River of the North: North Dakota, Minnesota
- Red River (Mississippi watershed): Texas, Oklahoma, Arkansas
- Rio Grande: New Mexico, Texas, Mexico
- Sabine River: Texas-Louisiana
- Salmon Falls River: New Hampshire, Maine
- St. Clair River: Michigan, Ontario
- St. Francis River (Missouri-Arkansas): Arkansas, Missouri
- St. Francis River (Quebec-Maine): Maine, Quebec
- St. John River: Maine, Quebec
- St. Lawrence River: New York, Ontario
- St. Louis River: Minnesota, Wisconsin
- St. Marys River (Florida-Georgia): Florida, Georgia
- St. Marys River (Michigan-Ontario): Michigan, Ontario
- Savannah River: South Carolina, Georgia
- Snake River: Idaho, Washington, Oregon
- St. Croix River (Maine-New Brunswick): Maine, New Brunswick
- St. Croix River (Wisconsin-Minnesota): Minnesota, Wisconsin
- Tug Fork River: Kentucky, West Virginia, Virginia
- Tugaloo River: Georgia, South Carolina
- Wabash River: Illinois, Indiana
