Charter Oak is an unincorporated community and census-designated place (CDP) in Los Angeles County, California, approximately 26 miles (42 km) east of downtown Los Angeles.

Originally a small agricultural settlement (primarily citrus orchards) centered on the intersection of Arrow Highway and Bonnie Cove Avenue, population growth greatly expanded the area recognized as "Charter Oak".

Since the 1960s, it has been known as a "bedroom community" suburb of Los Angeles and commercial agriculture is nearly gone.

Today, the generally accepted boundaries of historical Charter Oak are I-210 to the north, Valley Center Avenue to the east, Covina Hills Road to the south and Grand Avenue to the west, corresponding to the boundaries of Charter Oak Unified School District.

However, the actual CDP area is notably smaller in the present day.

[3] Charter Oak is primarily flat ground, though the South Hills of Glendora form much of the northern border, and there is a small valley in the southeast quadrant, with Walnut Creek flowing in the bottom.

The ground is described as "dry riverbed," with sandy soil which was suitable not only for the citrus orchards which once were the primary industry in the area, but also for several nurseries growing cactus and other small plants.

According to the United States Census Bureau, the CDP has a total area of 2.4 square kilometers (0.9 sq mi), all of it land.

Charter Oak Gymnastics has been a U.S. National Team training center since 1989, and has produced many elite athletes, including national champion Vanessa Atler and Olympian Jamie Dantzscher.

According to the 2010 United States Census, Charter Oak had a median household income of $68,597, with 8.3% of the population living below the federal poverty line.

In the California State Legislature, Charter Oak is in the 22nd Senate District, represented by Democrat Susan Rubio, and in the 48th Assembly District, represented by Democrat Blanca Rubio.