California's 21st State Assembly district

California's 21st State Assembly district
California's 21st State Assembly district
Current assemblymember
	Diane Papan ; D–San Mateo
Population (2020); • Voting age; • Citizen voting age	493,702; 390,302; 306,315
Demographics	36.65% White ; 2.10% Black ; 27.72% Latino ; 26.00% Asian ; 0.13% Native American ; 1.45% Hawaiian/Pacific Islander ; 0.79% other; 5.16% remainder of multiracial;
Registered voters	270,166
Registration	55.75% Democratic ; 14.15% Republican ; 24.59% No party preference

Last updated October 18, 2025

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%

Election results from statewide races

Year	Office	Results
2022	Governor	Newsom 74.8 – 25.2%
2022	Senator	Padilla 76.2 – 23.8%
2021	Recall ^[3]^[4]	50.1 - 49.9%
2021	Recall ^[3]^[4]	Elder 58.8 - 6.3%
2020	President ^[5]	Biden 55.3 – 42.3%
2018	Governor ^[6]	Newsom 54.6 – 45.4%
2018	Senator ^[7]	De Leon 54.3 – 45.7%
2016	President	Clinton 54.6 – 35.9%
2016	Senator	Harris 51.0 – 49.0%
2014	Governor	Brown 53.6 – 46.4%
2012	President	Obama 55.6 – 42.0%
2012	Senator	Feinstein 57.2 – 42.8%

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 2021 redistricting by the California Citizens Redistricting Commission.

Assembly members	Party	Years served	Counties represented	Notes
C. B. Culver	Republican	January 5, 1885 – January 3, 1887	Yolo
Levi B. Adams	Democratic	January 3, 1887 – January 5, 1891
Reese Clark	Republican	January 5, 1891 – January 5, 1893
H. C. Chipman		January 5, 1893 – January 7, 1895	Sacramento
L. T. Hatfield		January 7, 1895 – January 4, 1897
Scott F. Ennis		January 4, 1897 – January 2, 1899
William D. Knights		January 2, 1899 – January 1, 1901
Louis F. Reeber	Democratic	January 1, 1901 – January 5, 1903
Stephen H. Olmsted	Republican	January 5, 1903 – January 7, 1907	Marin
Edward I. Butler		January 7, 1907 – January 2, 1911
George H. Harlan		January 2, 1911 – January 6, 1913
Walter A. McDonald		January 6, 1913 – January 4, 1915	San Francisco
Walter A. McDonald	Prohibition	January 4, 1915 – January 8, 1917
Frederick C. Hawes	Republican	January 8, 1917 – January 5, 1931
Frank Lee Crist		January 5, 1931 – January 2, 1933	Santa Clara
Joseph P. Gilmore		January 2, 1933 – January 4, 1937	San Francisco
Joseph Francis Sheehan	Democratic	January 4, 1937 – January 2, 1939
Joseph P. Gilmore	Republican	January 2, 1939 – January 6, 1941
John D. Welch	Democratic	January 6, 1941 – January 4, 1943
Albert C. Wollenberg	Republican	January 4, 1943 – September 19, 1947		Resigned from the California State Assembly.^[8]
Vacant		September 19, 1947 – November 24, 1947
Arthur H. Connolly Jr.	Republican	November 24, 1947 – January 5, 1953		Won special election to fill the vacant seat left by Wollenberg. He was sworn in on November 24, 1947.^[9]
Caspar Weinberger		January 5, 1953 – January 5, 1959
Milton Marks		January 5, 1959 – October 25, 1966
Vacant		October 25, 1966 – January 2, 1967
Gordon W. Duffy	Republican	January 2, 1967 – November 30, 1974	Kings, Tulare
Victor Calvo	Democratic	December 2, 1974 – November 30, 1980	San Mateo, Santa Clara
Byron Sher	Democratic	December 1, 1980 – March 28, 1996		Resigned from the California State Assembly to take Oath of office in the California State Senate for the 11th district after winning a special election.^[10]
Vacant		March 28, 1996 – December 2, 1996
Ted Lempert	Democratic	December 2, 1996 – November 30, 2000
Joe Simitian		December 4, 2000 – November 30, 2004
Ira Ruskin		December 6, 2004 – November 30, 2010
Rich Gordon		December 6, 2010 – November 30, 2012
Adam Gray		December 3, 2012 – November 30, 2022	Merced, Stanislaus
Diane Papan		December 5, 2022 – present	San Mateo

Election results (1992–present)

2022

2022 California Assembly election
Primary election
Party		Candidate	Votes	%
	Democratic	Diane Papan	40,434	41.3
	Democratic	Giselle Hale	19,400	19.8
	Republican	Mark Gilham	19,078	19.5
	Democratic	James H. Coleman	11,269	11.5
	Democratic	Alison M. Madden	3,359	3.4
	Democratic	Maurice Goodman	2,664	2.7
	Green	Tania Solé	1,620	1.7
Total votes			97,824	100.0
General election
	Democratic	Diane Papan	94,676	72.4
	Democratic	Giselle Hale (withdrawn)	36,014	27.6
Total votes			130,690	100.0
	Democratic hold

2020

California State Assembly election, 2020
Primary election
Party		Candidate	Votes	%
	Democratic	Adam Gray (incumbent)	54,987	99.0%
	Republican	Joel Gutierrez Campos (write in)	300	0.5%
	Republican	Guadalupe Salazar (write in)	256	0.5%
Total votes			55,543	100.0%
General election
	Democratic	Adam Gray (incumbent)	93,816	59.6%
	Republican	Joel Gutierrez Campos	63,514	40.4%
Total votes			157,330	100.0%

2018

California State Assembly election, 2018
Primary election
Party		Candidate	Votes	%
	Democratic	Adam Gray (incumbent)	43,023	99.9
	Libertarian	Justin Ryan Quigley (write-in)	49	0.1
Total votes			43,072	100.0
General election
	Democratic	Adam Gray (incumbent)	74,320	71.3
	Libertarian	Justin Ryan Quigley	29,855	28.7
Total votes			104,175	100.0
	Democratic hold

2016

California State Assembly election, 2016
Primary election
Party		Candidate	Votes	%
	Democratic	Adam Gray (incumbent)	43,874	66.8
	Republican	Greg Opinski	21,754	33.1
	Republican	Brien J. Rahilly (write-in)	36	0.1
Total votes			65,664	100.0
General election
	Democratic	Adam Gray (incumbent)	85,990	69.8
	Republican	Greg Opinski	37,230	30.2
Total votes			123,220	100.0
	Democratic hold

2014

California State Assembly election, 2014
Primary election
Party		Candidate	Votes	%
	Democratic	Adam Gray (incumbent)	26,015	95.3
	Republican	Jack Mobley (write-in)	1,286	4.7
Total votes			27,301	100.0
General election
	Democratic	Adam Gray (incumbent)	34,931	53.4
	Republican	Jack Mobley	30,499	46.6
Total votes			65,430	100.0
	Democratic hold

2012

California State Assembly election, 2012
Primary election
Party		Candidate	Votes	%
	Republican	Jack Mobley	20,148	45.4
	Democratic	Adam Gray	14,391	32.4
	Democratic	Lesa Rasmussen	4,305	9.7
	Democratic	Tommy Jones	4,055	9.1
	Democratic	Robert R. Sellers	1,452	3.3
Total votes			44,351	100.0
General election
	Democratic	Adam Gray	63,349	58.2
	Republican	Jack Mobley	45,534	41.8
Total votes			108,883	100.0
	Democratic hold

2010

2010 California State Assembly election
Party		Candidate	Votes	%
	Democratic	Rich Gordon	89,927	60.1
	Republican	Greg Conlon	52,809	35.3
	Libertarian	Ray M. Bell, Jr.	6,295	4.6
Total votes			149,031	100.0
	Democratic hold

2008

2008 California State Assembly election
Party		Candidate	Votes	%
	Democratic	Ira Ruskin (incumbent)	133,856	70.93
	Republican	Annalisa Marie Temple	54,849	29.07
Total votes			188,705	100.00
Turnout				75.26
	Democratic hold

2006

2006 California State Assembly election
Party		Candidate	Votes	%
	Democratic	Ira Ruskin (incumbent)	95,104	67.77
	Republican	Virginia Kiraly	45,314	32.23
Total votes			140,418	100.00
Turnout				64.06
	Democratic hold

2004

2004 California State Assembly election
Party		Candidate	Votes	%
	Democratic	Ira Ruskin	98,002	51.55
	Republican	Steve Poizner	92,118	48.45
Total votes			190,120	100.00
	Democratic hold

2002

2002 California State Assembly election
Party		Candidate	Votes	%
	Democratic	Joe Simitian (incumbent)	71,110	60.53
	Republican	James A. Russell	42,164	35.89
	Libertarian	Raymond M. Bell, Jr.	4,210	3.58
Invalid or blank votes			6,201	5.01
Total votes			123,685	100.00
	Democratic hold

2000

2000 California State Assembly election
Party		Candidate	Votes	%
	Democratic	Joe Simitian	82,466	54.89
	Republican	Deborah E. G. Wilder	53,140	35.37
	Green	Gloria Purcell	14,641	9.74
Invalid or blank votes			6,295	4.02
Total votes			156,542	100.00
	Democratic hold

1998

1998 California State Assembly election
Party		Candidate	Votes	%
	Democratic	Ted Lempert (incumbent)	89,221	70.08
	Republican	Laverne F. Atherly	35,053	27.53
	Natural Law	Marilyn M. Bryant	3,036	2.38
Invalid or blank votes			10,995	7.95
Total votes			138,305	100.00
	Democratic hold

1996

1996 California State Assembly election
Party		Candidate	Votes	%
	Democratic	Ted Lempert (incumbent)	92,950	60.84
	Republican	Theodore A. Laliotis	52,855	34.59
	Natural Law	Ron Whitehurst	3,864	2.53
	Libertarian	Christopher R. Inama	3,115	2.04
Invalid or blank votes			12,320	7.46
Total votes			165,104	100.00
	Democratic hold

1994

1994 California State Assembly election
Party		Candidate	Votes	%
	Democratic	Byron D. Sher (incumbent)	79,188	62.64
	Republican	Bill Mills	47,219	37.35
	No party	Ronald Paul Whitehurst (write-in)	3	0.00
Invalid or blank votes			20,765	14.11
Total votes			147,175	100.00
	Democratic hold

1992

1992 California State Assembly election
Party		Candidate	Votes	%
	Democratic	Byron Sher (incumbent)	105,327	63.18
	Republican	Janice "Jan" LeFetra	55,497	33.29
	Libertarian	Lyn Sapowsky-Smith	5,887	3.53
Invalid or blank votes			18,028	9.76
Total votes			184,739	100.00
	Democratic hold

References

1 2 3 4 "Citizens Redistricting Commission Final Report, 2021" (PDF).
↑ "Report of Registration as of February 10, 2023" (PDF).
↑ "Supplement to the Statement of Vote September 14, 2021, California Gubernatorial Recall Election Counties by Congressional Districts for Recall Question" (PDF). Archived (PDF) from the original on March 7, 2022.
↑ "Counties by Congressional Districts for Recall Election Gubernatorial Replacement Candidates" (PDF).
↑ "Supplement to the Statement of Vote" (PDF). ca.gov. Retrieved September 17, 2023.
↑ "Supplement to the Statement of Vote" (PDF). ca.gov. Retrieved September 17, 2023.
↑ "Supplement to the Statement of Vote" (PDF). ca.gov. Retrieved September 17, 2023.
↑ "Albert Wollenberg". joincalifornia.com.
↑ "Arthur Connolly Oath of Office" (PDF). clerk.assembly.ca.gov.
↑ "Byron Sher Resignation letter" (PDF). clerk.assembly.ca.gov.

External links

District map from the California Citizens Redistricting Commission

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.

[population-1] 1 2 3 4 "Citizens Redistricting Commission Final Report, 2021" (PDF).

[voters-2] "Report of Registration as of February 10, 2023" (PDF).

[3] "Supplement to the Statement of Vote September 14, 2021, California Gubernatorial Recall Election Counties by Congressional Districts for Recall Question" (PDF). Archived (PDF) from the original on March 7, 2022.

[4] "Counties by Congressional Districts for Recall Election Gubernatorial Replacement Candidates" (PDF).

[5] "Supplement to the Statement of Vote" (PDF). ca.gov. Retrieved September 17, 2023.

[6] "Supplement to the Statement of Vote" (PDF). ca.gov. Retrieved September 17, 2023.

[7] "Supplement to the Statement of Vote" (PDF). ca.gov. Retrieved September 17, 2023.

[8] "Albert Wollenberg". joincalifornia.com.

[9] "Arthur Connolly Oath of Office" (PDF). clerk.assembly.ca.gov.

[10] "Byron Sher Resignation letter" (PDF). clerk.assembly.ca.gov.

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