Highgrove in Riverside County, California — The American West (Pacific Coastal)

Highgrove Hydroelectric Plant

Photographed by Michael Kindig, October 23, 2010

1. Highgrove Hydroelectric Plant Marker

Inscription. The first commercially significant hydroelectric plant in California, designed and built by Gustavus Olivio Newman, went into service here in 1888. Utilizing the flow of the Riverside Water Company Canal to produce about 225 kilowatts of power used for the arc light illumination of downtown streets in Riverside and Colton. The plant was destroyed by fire in 1915.

Erected 1991 by Native Sons and Daughters of the Golden West, #296, #241 and #299; Billy Holcomb Chapter No. 1069, E Clampus Vitus; and Riverside County Historical Commission. (Marker Number 24.)

Topics and series. This historical marker is listed in these topic lists: Charity & Public Work • Industry & Commerce • Waterways & Vessels. In addition, it is included in the E Clampus Vitus, and the Native Sons/Daughters of the Golden West series lists. A significant historical year for this entry is 1888.

Location. 34° 0.702′ N, 117° 20.4′ W. Marker is in Highgrove, California, in Riverside County. It is at the intersection of Iowa Avenue and Spring Street, on the right when traveling south on Iowa Avenue. Marker overlooks the Upper Warm Springs Canal. Touch for map. Marker is in this post office area: Riverside CA 92507, United States of America. Touch for directions.

Regionally, this marker is in Greater Los Angeles,

in the Inland Empire,

and in the Peninsular Ranges.

It is also in the American Southwest.

Globally, it is in North America,

on the Ring of Fire,

in the Pacific Rim,

in the Western Hemisphere,

in the Western World,

and in the Anglosphere.

Historically, it finds itself in what was once New Spain

and also Mexico’s Alta California.

Other nearby markers. At least 8 other markers are within 3 miles of this marker

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, measured as the crow flies: Trujillo Adobe (approx. 0.8 miles away); Agua Mansa Cemetery (approx. 2.4 miles away); Isidore and Marie Claire Camou (approx. 2½ miles away); Louis Robidoux (approx. 2½ miles away); Farm House Motel (approx. 2½ miles away); Harada House (approx. 2½ miles away); Civilian War Workers Memorial (approx. 2.6 miles away); Philip Brett (approx. 2.6 miles away).

Regarding Highgrove Hydroelectric Plant. After the initiation of Riverside's municipal direct current power system in 1896, the Highgrove plant also supplied some electricity to San Bernardino. In 1898, alternating current generators replaced the original direct current generators. Later the plant was merged into the Southern California Edison Company and only remnants are there now. SOURCE: Billy Holcomb Chapter 1069 35th Anniversary Plaque Book by Phillip Holdaway

Photographed by Michael Kindig, October 23, 2010

2. Highgrove Hydroelectric Plant Marker

Photographed by Adam Margolis, February 1, 2026

3. Highgrove Hydroelectric Plant Marker

Highgrove Hydroelectric Plant Location image. Click for full size.

Photographed by Adam Margolis, February 1, 2026

4. Highgrove Hydroelectric Plant Location

Credits. This page was last revised on June 11, 2026. It was originally submitted on December 19, 2011, by Michael Kindig of Elk Grove, California. This page has been viewed 2,031 times since then and 76 times this year. Photos: 1, 2. submitted on December 19, 2011, by Michael Kindig of Elk Grove, California. 3, 4. submitted on February 2, 2026, by Adam Margolis of Mission Viejo, California. • Syd Whittle was the editor who published this page.