| Beaver River | |
| Map: | Beaverriverpamap.png |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | Pennsylvania |
| Subdivision Type3: | Counties |
| Subdivision Name3: | Lawrence, Beaver |
| Subdivision Type5: | Cities |
| Subdivision Name5: | Beaver Falls, New Brighton, Rochester, Bridgewater |
| Length: | 21miles |
| Discharge1 Avg: | 4090.1cuft/s at mouth with Ohio River[1] |
| Source1: | Confluence of Mahoning River and Shenango River |
| Source1 Location: | Mahoningtown, New Castle |
| Source1 Coordinates: | 40.9581°N -80.3786°W |
| Source1 Elevation: | 760feet[2] |
| Mouth: | Ohio River |
| Mouth Location: | boundary of Bridgewater and Rochester |
| Mouth Coordinates: | 40.6969°N -80.2892°W |
| Mouth Elevation: | 682feet |
| Progression: | south |
| River System: | Ohio River |
| Basin Size: | [3] |
| Tributaries Left: | McKee Run Snake Run Connoquenessing Creek Thompson Run Bennett Run Blockhouse Run McKinley Run |
| Tributaries Right: | Edwards Run Jenkins Run Eckles Run Wampum Run Stockman Run Clarks Run Wallace Run Walnut Bottom Run Brady Run Hamilton Run |
Beaver River is a tributary of the Ohio River in Western Pennsylvania. Approximately 21 mi (34 km) long, it flows through a historically important coal-producing region north of Pittsburgh. The river is formed in Lawrence County by the confluence of the Mahoning and Shenango rivers in the Mahoningtown neighborhood of New Castle.[4] It flows generally south, past West Pittsburg and Homewood, then receives Connoquenessing Creek west of Ellwood City and flows past Beaver Falls and New Brighton. It joins the Ohio at Bridgewater and Rochester (flowing between those towns) at the downstream end of a sharp bend in the Ohio approximately 20 mi (32 km) northwest of (and downstream from) Pittsburgh. In the lower reaches near the Ohio River, the Beaver cuts through a gorge of underlying sandstone. The river is roughly parallel to the border with the state of Ohio, with both Interstate 376 and Pennsylvania Route 18 running parallel to the river itself.
The river, which flows throughout the northern half of Beaver County, is the namesake of the county[5] as well as several locales in both Beaver and Lawrence County. The river itself was either named for King Beaver (Tamaqua) of the Delaware nation that had migrated to the area in the late 1740s, or for the animal.[6] Until the partition of Lawrence County from parts of Beaver and Mercer County in 1849, the river was entirely in Beaver County, with its upstream terminus at the border between Beaver and Mercer County from 1800 to 1849.