| Arroyo Bayo | |
| Name Other: | Arroyo Bayou |
| Pushpin Map: | USA California |
| Pushpin Map Caption: | Location of the mouth in California |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | California |
| Subdivision Type3: | Region |
| Subdivision Name3: | Santa Clara County |
| Source1: | Just west of upper San Antonio Valley in the Diablo Range |
| Source1 Coordinates: | 37.335°N -121.4889°W |
| Source1 Elevation: | 2420feet |
| Mouth: | Confluence with San Antonio Creek to form Arroyo Valle |
| Mouth Coordinates: | 37.3856°N -121.5725°W |
| Mouth Elevation: | 1808feet |
| Tributaries Left: | Jack Canyon Creek, Blumbago Canyon Creek |
| Tributaries Right: | Bollinger Canyon Creek, Sawtooth Canyon Creek |
Arroyo Bayo is an 8adj=midNaNadj=mid[1] [2] perennial stream which flows northwest along Mount Hamilton Road east of Mt. Hamilton in the Diablo Range. It is part of the southern Alameda Creek watershed in Santa Clara County, California.
The historic Rancho Arroyo Bayo was located where Blumbago Canyon Creek joins Arroyo Bayo. The section of Mt. Hamilton Road east of Mt. Hamilton was known as Bayou Road on the historic Thomas and West map.[3] "Bayo" is Mexican Spanish for a dun, brown, or sorrel horse with a dark mane, tail and stripe on its back.[4]
Arroyo Bayo arises at 2240feet then flows west-northwest along Mount Hamilton Road then turns north where it is joined by San Antonio Creek to form Arroyo Valle. 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).[5]