This is a list of U.S. counties that are named for rivers and streams.

Counties named for rivers (alphabetical by county name)

A

• Alamance County, North Carolina: Alamance is named for Great Alamance Creek.
• Allegany County, New York: Allegany is a variant spelling of the Allegheny River.
• Alleghany County, North Carolina: Alleghany is a corruption of the Native American Delaware tribe's word for the Allegheny River, which is said to have meant a fine stream.
• Allegheny County, Pennsylvania: Allegheny is a corruption of the Native American Delaware tribe's word for the Allegheny River, which is said to have meant a fine stream.
• Amite County, Mississippi: Amite County is named for the Amite River.
• Appomattox County, Virginia: Appomattox is named for the Appomattox River, which is in turn named for the Appamatucks Native American people.
• Aroostook County, Maine: named for the Aroostook River.
• Ashtabula County, Ohio: Ashtabula was named for the Ashtabula River.
• Asotin County, Washington: Asotin is named for the Nez Percé name for Eel Creek.
• Auglaize County, Ohio: Auglaize is named for the Auglaize River.

B

• Beaver County, Oklahoma: Beaver is named for its county seat of Beaver, Oklahoma and the Beaver River, which flows through the county.
• Benzie County, Michigan is an Americanization of the French name, Riviere Aux-Bec-Scies, for the local river.
• Blanco County, Texas: Blanco is named for the Blanco River. Blanco means white in the Spanish language.
• Boise County, Idaho: Boise is named after the Boise River. Boise is French for "timber".
• Bosque County, Texas: Bosque is named for the Bosque River.
• Brazoria County, Texas: Brazoria is named for the Brazos River.
• Brazos County, Texas: Brazos is named for the Brazos River.
• Buffalo County, Wisconsin: Buffalo is named for the Buffalo River.

C

• Canadian County, Oklahoma: Canadian County is named for the Canadian River, which flows through the county.
• Cassia County, Idaho: Cassia is named after Cassia Creek.
• Cattaraugus County, New York:Cattargus County is named for Cattaraugus Creek
• Cedar County, Iowa: Cedar is named for the Cedar River.
• Chariton County, Missouri: Chariton is named from the Chariton River.
• Chattahoochee County, Georgia: Chattahoochee is named for the Chattahoochee River of Georgia, which also forms part of the Alabama-Georgia state line.
• Chattooga County, Georgia: Chattooga is named for the Chattooga River in northeast Georgia.
• Cheboygan County, Michigan is named for the Cheboygan River, which was itself a Native American name.
• Chippewa County, Minnesota is named after the Chippewa River, which flows through the county.
• Clear Creek County, Colorado: Clear Creek is named for Clear Creek, which runs through the county.
• Clearwater County, Idaho: Clearwater is named after the Clearwater River.
• Clearwater County, Minnesota is named after the Clearwater River and Clearwater Lake, which are both located within the county.
• Colorado County, Texas: Colorado is named for the Colorado River.
• Columbia County, Oregon: Named for the Columbia River which it borders.
• Columbia County, Washington: Columbia is named for the Columbia River.
• Coosa County, Alabama: Named for the Coosa River of Alabama & Georgia
• Cottonwood County, Minnesota is named after the Cottonwood River, which flows through the county.
• Costilla County, Colorado: Costilla is named for the Costilla River.
• Cuyahoga County, Ohio: Cuyahoga is named for the Cuyahoga River.
• Conecuh County, Alabama: Conecuh is named for the Conecuh River in southern Alabama.

D

• Des Moines County, Iowa: Des Moines is named for the Des Moines River.
• Deschutes County, Oregon: Deschutes is named for the Deschutes River.
• Dolores County, Colorado: Dolores is named for the Dolores River, originally Rio de Nuestra Senora de los Dolores, or, in English, "River of our Lady of Sorrows".
• DuPage County, Illinois is named after the DuPage River.

E

• Eagle County, Colorado: Eagle is named for the Eagle River.
• Elk County, Kansas: Elk is named for the Elk River.
• Escambia County, Florida: Escambia is named for the Escambia River.
• Escambia County, Alabama: Escambia, AL is also named for the Escambia River.

F

• Fluvanna County, Virginia: Fluvanna, VA is named for the Fluvanna River, a previous name for the James River. Fluvanna is Latin for Anne's River after Queen Anne of Great Britain.

G

• Gila County, Arizona: Gila is named for the Gila River.
• Grand County, Colorado: Grand is named for the Grand River, later renamed the Colorado River.
• Grand County, Utah: Grand is named for the Grand River, later renamed the Colorado River.
• Greenbrier County, West Virginia: Greenbrier is named for the Greenbrier River.

H

• Hillsborough County, Florida: Hillsborough is named for the Hillsborough River (Florida), which in turn is named after Wills Hill, Viscount Hillsborough, a British politician during the period of the American Revolutionary War who ordered the mapping of the river's course.
• Hocking County, Ohio: Hocking is named for the Hocking River.
• Hood River County, Oregon: Named for the Hood River, a river in the county.
• Humboldt County, Nevada: Humboldt is named for the Humboldt River, named in turn for Friedrich Heinrich Alexander von Humboldt, the famous German scientist, explorer and statesman.
• Hudson County, New Jersey: Hudson is named for the Hudson River, which in turn is named after Henry Hudson.

I

• Indian River County, Florida: Indian River is named for the Indian River, which is not a real river, but rather is a long, narrow saltwater lagoon between the mainland and the barrier islands.
• Iowa County, Iowa: Iowa is named for the Iowa River and the Iowa Native American tribe.

J

• Judith Basin County, Montana: Judith Basin is named for the Judith River.

K

• Kalamazoo County, Michigan is named for the Kalamazoo River. Kalamazoo is an Anglicized Native American word which probably meant boiling water.
• Kankakee County, Illinois: Kankakee is named after the Kankakee River.
• Kanabec County, Minnesota: Kanabec is named after the Snake River, which flows through the area. Kanabec is Ojibwa for snake.
• Kanawha County, West Virginia: Kanawha is named for the Kanawha River.
• Kennebec County, Maine: Kennebec is named for the Kennebec River.
• Kern County, California: Kern is named after the Kern River, which is named in turn for Edward M. Kern, a topographer who accompanied John C. Frémont on an early expedition through the state.
• Keya Paha County, Nebraska: Keya Paha is named for the Dakota words Ké-ya Pa-há Wa-kpá, which, translated, mean Turtle Hill River.
• Kings County, California: Kings is named for the Kings River.
• Koochiching County, Minnesota is named after a Cree word of uncertain meaning given by Ojibwas to Rainy River.

L

• Lackawanna County, Pennsylvania: Lackawanna is named after the Lackawanna River.
• Las Animas County, Colorado: Las Animas is named for the Las Animas River, originally El Rio de las Animas Perdidas en Purgatorio, or, in English, "River of the Souls Lost in Purgatory".
• Latah County, Idaho: Latah is named after Latah Creek.
• Lehigh County, Pennsylvania: Leigh is named after the Lehigh River; a tributary of the Delaware River.
• Limestone County, Alabama: Limestone is named for Limestone Creek, which runs through the county and has a bed of limestone.
• Little River County, Arkansas: Little River is named for the Little River.
• Loup County, Nebraska: Loup is named for the Loup River.

M

• Mahoning County, Ohio: Mahoning is named for the Mahoning River.
• Malheur County, Oregon: Malheur is named for the Malheur River.
• Manistee County, Michigan was named for the Manistee River, which in turn had Native American name meaning river at whose mouth there are islands.
• Maries County, Missouri: Maries is named from the Maries River.
• Merrimack County, New Hampshire: Merrimack is named for the Merrimack River.
• Mississippi County, Arkansas: Mississippi is named for the Mississippi River.
• Mississippi County, Missouri: Mississippi is named after the Mississippi River.
• Moniteau County, Missouri: Montineau is named after Moniteau Creek.
• Monongalia County, West Virginia: Monongalia is named for the Monongahela River.
• Muskegon County, Michigan is named for the Muskegon River, named for the Ojibwa language word meaning swamp or marsh.
• Musselshell County, Montana: Musselshell is named for the Musselshell River, named in turn by the Lewis and Clark Expedition presumably due to mussels found on its banks.

N

• Nemaha County, Kansas: Nemaha is named for the Nemaha River.
• Nemaha County, Nebraska: Nemaha is named for Nimaha, the Oto name meaning miry water for a stream which crossed the county and emptied into the Missouri River.
• Neosho County, Kansas: Neosho is named for the Neosho River.
• Niobrara County, Wyoming: Niobrara is named for the Niobrara River. Niobrara is Omaha for flat or broad river.
• Nodaway County, Missouri: Nodaway is named from the Nodaway River. Nodaway is a Potawatomi word meaning placid.

O

• Oconee County, Georgia: Oconee is named for the Oconee River that forms part of the county's border
• Ohio County, Indiana: Ohio is named for the Ohio River.
• Ohio County, Kentucky: Also named for the Ohio River. When the county was formed, the river formed its northern boundary, but no longer does after several new counties were carved from it.
• Ohio County, West Virginia: Also named for the Ohio River.
• Ontonagon County, Michigan is named for a river called Nantounagon on an early French map.
• Otter Tail County, Minnesota: Otter Tail is named after Otter Tail Lake and Otter Tail River. The river was named by the Ojibwa for its long sandbar shaped like an otter's tail.
• Osage County, Kansas: Osage is named for the Osage River.
• Oswego County, New York: Oswego is named for the Oswego River.
• Ouachita County, Arkansas: Ouachita is named for the Ouachita River.
• Ouachita Parish, Louisiana: named for the Ouachita River

P

• Payette County, Idaho: Payette is named after the Payette River, which, in turn, is named for explorer Francois Payette.
• Pearl River County, Mississippi: Named for the Pearl River, obviously
• Pecos County, Texas: Pecos [pey-kuhs] is named after the Pecos River. The name "Pecos" derives from the Keresan (Native American language) term for the Pecos Pueblo, [p'æyok'ona].
• Platte County, Nebraska: Platte is named for the Platte River.
• Platte County, Wyoming: Platte is named for the North Platte River. Platte is French for flat.
• Plumas County, California: Plumas is named for Spanish name for the Feather River (Rio de las Plumas), which flows through the county.
• Powder River County, Montana: Powder River is named for the Powder River, which in turn was named for gunpowder-like sand along its banks.

R

• Racine County, Wisconsin: Racine is named for the Root River, racine being the French word for root.
• Rappahannock County, Virginia: Rappahannock is named for the Rappahannock River, named in turn for the Rappahannock Native American people.
• Red Lake County, Minnesota: Red Lake County is named after the Red Lake River, named by the Ojibwa for its reddish sand and water.
• Red River County, Texas: Red River is named for the Red River.
• Red River Parish, Louisiana: named for the Red River
• Redwood County, Minnesota: Redwood County is named after the Redwood River, which flows through the county.
• Republic County, Kansas: Republic is named for the Republican River, which in turn was named for the Pawnee Republic which once existed near the river.
• Rio Arriba County, New Mexico: Rio Arriba is named for its location on the upper Rio Grande. (Rio Arriba is "upper river" in Spanish.)
• Rio Blanco County, Colorado: Rio Blanco is named for Rio Blanco, or, in English, the White River.
• Rio Grande County, Colorado: Rio Grande is named for the Rio Grande, which runs through the county.
• Rock County, Wisconsin: Rock is named for the Rock River.
• Roseau County, Minnesota: Roseau County is named after the Roseau Lake and Roseau River.
• Rosebud County, Montana: Rosebud is named for the Rosebud River, which was named for the many wild roses along the banks of the river.

S

• Sacramento County, California: Named for the Sacramento River
• Saline County, Arkansas: Named for the Saline River.
• Saline County, Illinois: Named for the Saline River.
• Saline County, Kansas: Named for the Saline River.
• San Benito County, California: Named for San Benito Creek.
• San Juan County, Colorado: Named for the San Juan River and San Juan Mountains.
• San Juan County, New Mexico: Named for the San Juan River.
• San Miguel County, Colorado: Named for the San Miguel River.
• Santa Cruz County, Arizona: Named for the Santa Cruz River.
• Sangamon County, Illinois Named for the Sangamon River.
• Scioto County, Ohio: Named for the Scioto River.
• Sevier County, Utah: Named for the Sevier River.
• Shenandoah County, Virginia: Named for the Shenandoah River; Shenandoah is a Native American term meaning beautiful daughter of the stars.
• Shiawassee County, Michigan: Shiawassee is named for the Shiawassee River.
• St. Francis County, Arkansas: St. Francis is named for the St. Francis River.
• St. Johns County, Florida: St. Johns is named for the St. Johns River.
• St. Joseph County, Indiana: St. Joseph is named for the St. Joseph River.
• St. Joseph County, Michigan: St. Joseph is named for the St. Joseph River
• St. Lawrence County, New York: St. Lawrence is named for the St. Lawrence River.
• St. Louis County, Minnesota: St. Louis is named after the St. Louis River.
• Stillwater County, Montana: Stillwater is named for the Stillwater River, named for its very slow current.
• Susquehanna County, Pennsylvania named after the Susquehanna River.
• Suwannee County, Florida: Suwannee is named for the Suwannee River, the same river made famous by Stephen Foster in his song Old Folks at Home.
• Sweetwater County, Wyoming: Sweetwater is named for the Sweetwater River.

T

• Tallapoosa County, Alabama: Named for the Tallapoosa River. Tallapoosa is believed to be a Choctaw word meaning pulverized rock.
• Tangipahoa Parish, Louisiana: Named for the Tangipahoa River
• Tensas Parish, Louisiana: Named for the Tensas River
• Tioga County, Pennsylvania: Named for the Tioga River
• Tippecanoe County, Indiana: Tippecanoe is named for the Tippecanoe River and the Battle of Tippecanoe.
• Tuscaloosa County, Alabama: Tuscaloosa was a Native American name for the Black Warrior River.
• Tuscarawas County, Ohio: Tuscarawas is named for the Tuscarawas River.

V

• Vermilion County, Illinois: Vermilion is named for both the Vermilion River and the Little Vermilion River.

W

• Wabash County, Indiana: Wabash is named for the Wabash River.
• Wabash County, Illinois: Wabash is named for the Wabash River.
• Wicomico County, Maryland: Wicomico is named for the Wicomico River. In Lenape, wicko mekee indicated a place where houses are built, possibly in reference to a settlement.

Y

• Yamhill County, Oregon: Yamhill is named after the Yamhill River.^{[citation needed]}
• Yellow Medicine County, Minnesota: Yellow Medicine County is named after the Yellow Medicine River, which flows through the county.

Counties possibly named for rivers

• Cumberland County, Illinois: Cumberland is named for either the Cumberland River or the Cumberland Road.
• San Juan County, Utah: San Juan is possibly named for the San Juan River.
• Skamania County, Washington: Skamania is named for a Chinookan word meaning swift water.

Counties indirectly named for rivers

• Aroostook County, Maine: Aroostook is named for a Native American word meaning beautiful river.
• Canyon County, Idaho: Canyon is named after either the Boise River or Snake River canyons.
• Coös County, New Hampshire: Coös is named for a Native American word meaning crooked, in reference to a bend in the Connecticut River.
• Crow Wing County, Minnesota: Crow Wing is named after an island shaped like a raven's wing at the junction of the Crow Wing River and Mississippi River.
• Huerfano County, Colorado: Huerfano is named for Huerfano Butte, as was the Huerfano River. Huerfano is orphan in Spanish.
• Merced County, California: Merced is named for the Spanish word for mercy, and was named by Spanish explorers in gratitude for water of the Merced River, which was found after a dry 40-mile trek.
• Muskingum County, Ohio: Muskingum is a Delaware word meaning by the river side.
• Riverside County, California: Riverside is named for the city of Riverside, the county seat, which in turn was named for its location beside the Santa Ana River.
• Sagadahoc County, Maine: Sagadahoc is named for a Native American word meaning mouth of big river.
• Twin Falls County, Idaho: Twin Falls is named after the double falls along the Snake River.
• Yellowstone County, Montana: Yellowstone is named for the yellow rocks found along what is now known as the Yellowstone River.