Sabine (săbēnˈ) [key], river, c.575 mi (925 km) long, rising on the prairies NE of Dallas, Tex. It flows SE across Texas, then south to mark the Texas–Louisiana line. Near its mouth it broadens to form Sabine Lake (c.17 mi/27 km long; c.7 mi/11.3 km wide), then goes through Sabine Pass to the Gulf of Mexico. The Neches River flows into the lake. Port Arthur, Tex., is on Sabine Lake, and Orange, Tex., is on the river. The Sabine–Neches Canal divides above Port Arthur, the west branch leading up the Neches River to Beaumont and the east branch flowing to Orange. Part of the Intracoastal Waterway, it permits oceangoing vessels to reach these cities.