Arroyo Bayo is an 8-mile-long (13 km)[2][3] perennial stream which flows northwest along Mount Hamilton Road east of Mt.

It is part of the southern Alameda Creek watershed in Santa Clara County, California.

[5] "Bayo" is Mexican Spanish for a dun, brown, or sorrel horse with a dark mane, tail and stripe on its back.

Arroyo Valle flows north through Lake Del Valle to the Livermore Valley where it turns west to Arroyo de la Laguna at Interstate 680, ultimately joining Alameda Creek and terminating in San Francisco Bay.

Informal surveys of Arroyo Bayo have found no steelhead trout (Oncorhynchus mykiss).