Alum Rock Falls is one of the recorded waterfalls on Upper Penitencia Creek in Santa Clara County, California, in the Central California Foothills and Coastal Mountains region. It lies about 2.3 miles northeast of East Foothills and roughly 6.7 miles east of Milpitas as the crow flies.
No height measurement has been recorded for it yet.
The Central California Foothills and Coastal Mountains are rolling hills and low ranges of oak woodland, chaparral and grassland with a Mediterranean climate of wet winters and dry summers. Streams are seasonal, and waterfalls run strongest after winter and spring rains.
There are 8 recorded waterfalls in Santa Clara County. Arroyo Aguague Falls, is about 1 miles away. Murietta Falls, 100 feet high, is about 9.7 miles away. Arroyo Mocho Falls, 35 feet high, is about 15.3 miles away.
Alum Rock Falls is located at 37.4051° N, 121.7889° W. The listing is based on the World Waterfall Database, one of the sources compiled by the U.S. Geological Survey in its inventory of waterfalls and rapids of the conterminous United States. The creek name is confirmed against the federal Geographic Names Information System. The exact position has not yet been verified on aerial imagery, so treat the map pin as approximate. Details on trails, parking and access have not been documented for this waterfall yet.