Ontario in San Bernardino County, California — The American West (Pacific Coastal)

United States Post Office

123 West Holt Boulevard

— 1940 —

United States Post Office Marker image. Click for full size.

Photographed by Craig Baker

1. United States Post Office Marker

Inscription. The Downtown Post Office was designed in a modern Spanish Revival architectural style by Los Angeles architect, Louis A. Simon, and constructed with funds from the Works Progress Administration (WPA). There are two vividly-colored murals in the lobby depicting periods from Ontario's early settlement and WWII. The murals were painted by local artist Nellie G. Best in 1942 and funded through the Treasury Department's Section of Fine Arts. Ontario's Postmaster Carl J. Hase mailed the first letter from this facility on April 19, 1941.

Erected 1998 by City of Ontario, California. (Marker Number 39.)

Topics and series. This historical marker is listed in these topic lists: Architecture • Arts, Letters, Music • Charity & Public Work • Communications. In addition, it is included in the Works Progress Administration (WPA) projects series list. A significant historical date for this entry is April 19, 1941.

Location. 34° 3.792′ N, 117° 39.129′ W. Marker is in Ontario, California, in San Bernardino County. It is at the intersection of West Holt Boulevard (Business Interstate 10) and South Laurel Avenue, on the right when traveling

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east on West Holt Boulevard. Touch for map. Marker is at or near this postal address: 123 W Holt Blvd, Ontario CA 91762, United States of America. Touch for directions.

Regionally, this marker is in Greater Los Angeles,

in the Inland Empire,

in the Peninsular Ranges,

and specifically in the Transverse 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 walking distance of this marker: The Old Post Office / Paul Williams Building (within shouting distance of this marker); McCann Block Building (within shouting distance of this marker); Frankish Building (about 300 feet away, measured in a direct line); Nine Young Pepper Trees (about 400 feet away); Mule Car (about 600 feet away); Old City Hall (about 700 feet away); Dr. O.S. Ensign House (approx. 0.2 miles away); Ontario Masonic Hall (approx. 0.2 miles away). Touch for a list and map

Photographed by Duane and Tracy Marsteller, September 28, 2025

2. United States Post Office Marker

of all markers in Ontario.

United States Post Office and Marker image. Click for full size.

Photographed by Duane and Tracy Marsteller, September 28, 2025

3. United States Post Office and Marker

The marker is to the right of the door.

Photographed by Craig Baker

4. United States Post Office and Marker

Mural in Lobby image. Click for full size.

Photographed by Craig Baker

5. Mural in Lobby

Credits. This page was last revised on January 8, 2026. It was originally submitted on November 9, 2025, by Duane and Tracy Marsteller of Murfreesboro, Tennessee. This page has been viewed 63 times since then and 33 times this year. Photos: 1. submitted on January 3, 2026, by Craig Baker of Sylmar, California. 2, 3. submitted on November 9, 2025, by Duane and Tracy Marsteller of Murfreesboro, Tennessee. 4, 5. submitted on January 8, 2026, by Craig Baker of Sylmar, California.