California's 42nd State Assembly district is one of 80 California State Assembly districts.

It is currently represented by Democrat Jacqui Irwin.

The district straddles the gateway between the Inland Empire and the California desert, stretching from Yucaipa and Hemet in the west to the Twentynine Palms region and western Coachella Valley in the east.

Due to redistricting, the 42nd district has been moved around different parts of the state.

The current iteration resulted from the 2011 redistricting by the California Citizens Redistricting Commission.