Sierra Madre is a city in Los Angeles County, California whose population was 10,917 at the 2010 U.S. Census, up from 10,580 at the time of the 2000 U.S. Census. The city is located in the foothills of the San Gabriel Valley below the southern edge of the Angeles National Forest. Pasadena and Altadena are to its west, with Arcadia to its south and east. Sierra Madre is known as "Wisteria City", and its city seal is decorated with a drawing of the now widely known 500-foot (150 m) vine.