Guasti, California


Guasti, formerly known as South Cucamonga and Zucker, is a formerly unincorporated community in the Cucamonga Valley region of the Pomona Valley, in southwestern San Bernardino County, California. It has since been annexed into the city of Ontario. It is located 3.5 miles (5.6 km) east of downtown Ontario and near the Ontario International Airport.

Guasti, California
Official seal of Guasti, California
Guasti, California is located in California
Guasti, California
Guasti, California
Coordinates: 34°03′54″N 117°35′11″W / 34.06500°N 117.58639°W / 34.06500; -117.58639Coordinates: 34°03′54″N 117°35′11″W / 34.06500°N 117.58639°W / 34.06500; -117.58639
Country United States
State California
County San Bernardino
296 m (971 ft)
Time zoneUTC-8 (Pacific (PST))
 • Summer (DST)UTC-7 (PDT)
ZIP code
91761, 91743
Area code(s)909
GNIS feature ID1660703[1]

The area was a former major wine-producing district in the Cucamonga Valley AVA region, with the Italian Vineyard Company based here. By 1917 the Cucamonga-Guasti vineyards spanned over 20,000 acres, and Secondo Guasti was advertising his vineyard as "The Largest in the World."[2]

The community changed its name from Zucker to Guasti after Secondo Guasti, founder of the Italian Vineyard Company, which operated in the area. The Guasti post office opened in 1910.[3]

Post OfficeEdit

Guasti has a post office with ZIP code 91743.[4] However, the area is now located in the area of ZIP code 91761, presumably after its annexation into Ontario.[5] The first post office in the community opened under the name Zucker in 1887 and closed in 1900.


  1. ^ "US Board on Geographic Names". United States Geological Survey. 2007-10-25. Retrieved 2008-01-31.
  2. ^ Inside The Inland Empire: "The Wineries of Rancho Cucamonga are back.", 9 May 2007.
  3. ^ Durham, David L. (1998). California's Geographic Names: A Gazetteer of Historic and Modern Names of the State. Quill Driver Books. p. 1424. ISBN 1-884995-14-4.
  4. ^ ZIP Code Lookup
  5. ^ "Ontario, CA 91761".