San Gabriel National Forest was established as the San Gabriel Forest Reserve by the General Land Office in California on December 20, 1892 with 555,520 acres (2,248.1 km2). After the transfer of federal forests to the U.S. Forest Service in 1905, it became a National Forest on March 4, 1907.
On July 1, 1908 part of the forest was combined with Angeles National Forest and the remainder with Santa Barbara National Forest, and the name was discontinued.
References
San Gabriel National Forest Wikipedia(Text) CC BY-SA