Riding profile

CA-21

US House district — CA · Mixed · us ca

The question

CA-21: a safe seat for the Democrats?

Editorial read

CA-21, a mixed riding in CA, elected a member with the Democrats in the previous cycle, with a 7-point margin. The Vote-Scope model projects the Democrats ahead at 56% vote share, against 44% for the Republicans, and the probability of a close race is negligible.

Sitting member

COSTA, JIM

Sits with Democrat

Who's running

The candidates

Declared and on-ballot candidates for the upcoming election.

  • Democrat Incumbent

    Costa, Jim

  • Republican Challenger

    Kirkland, Kyle

  • Republican Challenger

    Rios, Lorenzo

Current forecast

Democrat

Safe

Probability
100%
Mean margin (pts)
11.5
P(close race)
0%

Projected vote share

Projection by party

  • Democrat 55.8%
  • Republican 44.3%

In context

How this riding stacks up

Democrat Republican
HereCA-21 55.8%44.3%
National averageUnited States 51.9% +3.9 46.6% −2.4

Nationwide averages computed across the 435 riding-level projections (unweighted mean).

Projection track

How the projection has moved

Previous election · US HOUSE_2024

Won by
Democrat
Margin
7.3 pts
Margin shift vs current projection
+4.2 pts

Around the region

Nearby ridings

Tone only — pick a riding to see the numbers.

Last model run
Cycle
us_house_2026