The district is based in Orange and Los Angeles counties and includes all of Garden Grove, Westminster, Cerritos, Buena Park, Placentia, Hawaiian Gardens, Cypress, Fountain Valley, Artesia, Los Alamitos, Rossmoor, and La Palma, as well as parts of Brea, Lakewood, and Fullerton.

On February 25, 2018, UC Irvine (UCI) assistant law professor Dave Min received the endorsement of the California Democratic Party.

[3] Min, former White House senior technology advisor Brian Forde,[4] former legislative assistant to Sherrod Brown (D-OH) Kia Hamadanchy,[5] UCI law professor Katie Porter,[6] and UCI business professor John Graham ran in the "top two" primary in June 2018.

On November 14, 2018, eight days after polls closed, Dave Wasserman, then the House Editor for The Cook Political Report, projected that Porter had won the general election.

The district included the communities of Palm Springs, Moreno Valley, Palm Desert, Hemet, Cathedral City, Temecula, Blythe, Rancho Mirage, Murrieta, Indio, Indian Wells, La Quinta, Cabazon, Anza, Thermal, Idyllwild, Coachella, and other unincorporated areas of Riverside County.