Waldon is a former census-designated place (CDP) in Contra Costa County, California, United States.

It is served by Pleasant Hill/​Contra Costa Centre station on the Bay Area Rapid Transit (BART) Yellow Line, and by Interstate 680.

The area has been undergoing a series of transit-oriented development projects under the auspices of the Contra Costa Centre Transit Village public/private partnership.

Waldon's territory has been assumed by Contra Costa Centre CDP for the 2010 census.

According to the United States Census Bureau, the CDP had a total area of 0.7 square miles (1.8 km2), all of it land.