San Gabriel River (California)
For the river in Texas, see San Gabriel River (Texas). San Gabriel River The channelized San Gabriel River in Los Alamitos, near its confluence with Coyote Creek Map of the San Gabriel (yellow) and Rio Hondo (purple) watersheds. Location Country United States State California Counties Los Angeles County, Orange County Physical characteristics Source East Fork San Gabriel River - location Angeles National Forest, San Gabriel Mountains - coordinates 34°20′35″N 117°43′30″W / 34.34306°N 117.72500°W / 34.34306; -117.72500 [1] - elevation 4,493 ft (1,369 m) Mouth Pacific Ocean - location Alamitos Bay, Long Beach/Seal Beach - coordinates 33°44′33″N 118°06′56″W / 33.74250°N 118.11556°W / 33.74250; -118.11556 [1] - elevation 0 ft (0 m) Length 58 mi (93 km) [2] Basin size 689 sq mi (1,780 km 2 ) [5] Discharge - location above Whittier Narrows Dam [3] - average 185 cu ft/s (5.2 m