California's 21st State Assembly district

California's 21st State Assembly district is one of 80 California State Assembly districts. It is currently represented by Democrat Diane Papan of San Mateo.

District profile
The district includes most of San Mateo County, California.

Most of San Mateo County – 64.50%
 * Atherton – 2.77%
 * Belmont
 * Brisbane
 * Burlingame
 * East Palo Alto
 * Foster City
 * Hillsborough
 * Menlo Park – 19.41%
 * Millbrae
 * Redwood City
 * San Bruno – 95.76%
 * San Carlos
 * San Mateo
 * South San Francisco – 50.20%

Unincorporated San Mateo County
 * Baywood Park
 * Emerald Lake Hills
 * Highlands
 * North Fair Oaks
 * Remainder of San Mateo County – 27.82%

List of assembly members
Due to redistricting, the 21st district has been moved around different parts of the state. The current iteration resulted from the 2011 redistricting by the California Citizens Redistricting Commission.

Election results (1992–present)
1992 · 1994 · 1996 · 1998 · 2000 · 2002 · 2004 · 2006 · 2008 · 2010 · 2012 · 2014 · 2016 · 2018 · 2020 · 2022