Arroyo Hondo is a northwestward-flowing 13-mile-long (20.9 km)[2] river in Santa Clara County, California, United States, that lies east of Milpitas.

When William Henry Brewer and Charles Hoffman of the Whitney Survey climbed the peak on August 26, 1861, they did not know it had a name, and christened it Mt.

Arroyo Hondo still has remnants of native coastal rainbow trout (Oncorhynchus mykiss irideus), which several conservation organizations have attempted to protect.

Impassable falls are now present on upper Arroyo Hondo, but the rainbow trout in its Smith and Isabel creek tributaries are assumed to be native, as California roach (Hesperoleucus symmetricus) and Sacramento sucker (Catostomus occidentalis occidentalis) are also present above and below the falls.

[8] Also, both Smith Creek and Arroyo Hondo were recorded in 1905 by John Otterbein Snyder as anadromous steelhead trout (Oncorhynchus mykiss irideus) streams.