As of the 2020 redistricting, California's 48th congressional district is located in Southern California. The district encompasses some of the East County and all of the Mountain Empire areas of San Diego County, and part of southwestern Riverside County.
San Diego County is split between this district, the 49th district, the 50th district, the 51st district, and the 52nd district. The 48th and 49th are partitioned by Gavilan Mountain Rd, Sandia Creek Dr, De Luz Rd, Marine Corps Base Pendleton, Sleeping Indian Rd, Tumbleweed Ln, Del Valle Dr, Highland Oak St, Olive Hill Rd, Via Puerta del Sol, N River Rd, Highway 76, Old River Rd, and Little Gopher Canyon Rd.
The 48th and 50th are partitioned by Gopher Canyon Rd, Escondido Freeway, Mountain Meadow Rd, Hidden Meadows, Reidy Cyn, N Broadway, Cougar Pass Rd, Adagio Way, Calle Ricardo, Tatas Place, Rue Montreux, Jesmond Dene Rd, Ivy Dell Ln, N Centre City Parkway, Highway 15, Richland Rd, Vista Canal, Woodland Parkway, W El Norte Parkway, Bennett Ave, Elser Ln, Nordahl Rd, Calavo Dr, Deodar Rd, Highway 78, Barham Dr, 2315-2339 Meyers Ave, Hill Valley Dr, County Club Dr, Auto Park Way, Highway 56, N Centre City Parkway, W Valley Parkway, N Juniper St, Highway 78, N Hickory St, E Mission Ave, Martin Dr, E Lincoln Ave, N Ash St, E Grand Ave, Bear Valley Parkway, Old Guerjito Rd, San Pasqual Battlefield State Historic Park, San Pasqual Trails Openspace, San Dieguito River Park, Bandy Canyon Rd, Santa Maria Creek, Highland Valley Rd, West Ridge Trail, Palmer Dr/Summerfield Ln, Pomerado Rd, and Carmel Mountain Ranch Openspace.
The 48th and 51st are partitioned by Sabre Springs Openspace, Scripps Miramar Openspace, Beeler Canyon Rd, Sycamore Canyon Openspace, Weston Rd, Boulder Vis, Mast Blvd, West Hills Parkway, San Diego River, Highway 52, Simeon Dr, Mission Trails Openspace, Fanita Dr, Farmington Dr, Lund St, Nielsen St, Paseo de Los Castillos, Gillespie Air Field, Kenney St, San Vicente Freeway, Airport Dr, Wing Ave, W Bradley Ave, Vernon Way, Hart Dr, Greenfield Dr, E Bradley Ave, 830 Adele St-1789 N Mollison Ave, Peppervilla Dr/N Mollison Ave, Pepper Dr, Greta St/Cajon Greens Dr, N Mollison Ave/Buckey Dr, Denver Ln, Broadway Channel, N 2nd St, Flamingo Ave/Greenfield Dr, Dawnridge Ave/Cresthill Rd, Groveland Ter/Camillo Way, Sterling Dr, Kumeyaay Highway, E Madison Ave, Granite Hills Dr, E Lexington Ave, Dehesa Rd, Vista del Valle Blvd, Merritt Ter, E Washington Ave, Merritt Dr, Dewitt Ct, Emerald Heights Rd, Foote Path Way, Highway 8, Lemon Ave, Lake Helix Dr, La Cruz Dr, Carmichael Dr, Bancroft Dr, Campo Rd, and Sweetwater River.
Riverside County is split between this district and the 41st district. They are partitioned by Ortega Highway, Tenaja Truck Trail, NF-7506, Tenaja, San Mateo Creek, Los Alamos Rd, Und 233, S Main Dv, Wildomar, Grand Ave, Rancho Mirlo Dr, Copper Canyon Park, 42174 Kimberly Way-35817 Darcy Pl, Escondido Expressway, Scott Rd, 33477 Little Reb Pl-33516 Pittman Ln, Keller Rd, Menifee Rd, Clinton Keith Rd, Max Gilliss Blvd, Highway 79, Borel Rd, Lake Skinner, Warren Rd, Summitville St, Indian Knoll Rd, E Benton Rd, Rancho California Rd, Overhill Rd, Green Meadow Rd, Crossover Rd, Exa-Ely Rd, Denise Rd, Wiley Rd, Powerline Rd, Wilson Valley Rd, Wilson Creek, Reed Valley Rd, Centennial St, Beaver Ave, and Lake Vista Dr. The 48th district takes in the cities of Temecula and Murrieta and the census-designated places Aguanga and Lake Riverside.