As of the 2020 redistricting, California's 28th congressional district is located in Southern California. It encompasses most of north eastern Los Angeles County, and part of the eastern border of San Bernardino. A majority of the district is taken up by Angeles National Forest.
The 28th and 30th are partitioned by Angeles National Forest, Big Tujunga Creek, Big Tujunga Canyon Rd, Silver Creek, Markridge Rd, Pennsylvania Ave, Northwoods Ln, Ramsdell Ave, Fairway Ave, La Crescenta Ave, Mayfield Ave, Rosemont Ave, Florencita Ave, Thompson Ct, Park Pl, Verdugo Blvd, La Tour Way, Descanso Gardens, Norham Pl, Wendover Rd, Linda Vista Ave, Oak Grove Dr, Yucca Ln, W Montana St, Vermont St, Forest Ave, Wyoming St, Lincoln Ave, Anderson Pl, Canada Pl, Highway 210, W Hammond St, Glen Ave, W Mountain St, Manzanita Ave, N Orange Grove Blvd, and Ventura Freeway.
The 28th and 31st are partitioned by Rio Hondo River, Garvey Ave, Highway 19, Highway 10, Eaton Wash, Temple City Blvd, Valley Blvd, Ellis Ln, Lower Azusa Rd, Grande Ave, Santa Anita Ave, Lynrose St, Flood Control Basin, Peck Rd, Randolph St, Cogswell Rd, Clark St, Durfree Ave, Santa Anita Wash, S 10th Ave, Jeffries Ave, Mayflower/Fairgreen Ave, Alta Vista/Fairgreen Ave, El Norte Ave, S 5th Ave, Valencia Way/N 5th Ave, Hillcrest Blvd, E Hillcrest Blvd, Grand Ave, E Greystone Ave, N Bradoaks Ave, Angeles National Forest, W Fork Rd, Highway 39, Cedar Creek, Iron Fork, Glendora Mountain Rd, Morris Reservoir, W Sierra Madre Ave, N Lorraine Ave, E Foothill Blvd, E Carroll Ave, Steffen St, S Lorraine Ave, AT and SF Railway, E Route 66, N Cataract Ave, San Dimas Canyon Rd, Clayton Ct, Live Oak Canyon, Rotary Dr, Highway 30, Williams Ave, Highway 210, Garey Ave, and Summer Ave.
The 28th and 34th are partitioned by Colorado Blvd, Lantana Dr, Church St, Adelaide Pl, Highway 110, N Huntingdon Dr, S Winchester Ave, Valley Blvd, Laguna Channel, Highway 710, l-10 Express Ln, Rollins Dr, Floral Dr, E Colonia, Belvedere Park, Highway 60, S Atlantic Blvd, and Pomona Blvd.
The 28th and 35th are partitioned by Towne Ave, Harrison Ave, Carnegie Ave, W Arrow Highway, Mountain Ave, and E American Ave.
San Bernardino County is split between this district, the 23rd district, the 33rd district, and the 35th district. They are partitioned by San Bernardino National Forest, Manzanita Rd, Highway 15, Cajon Blvd, W Kenwood Ave, Highway 215, W Meyers Rd, Ohio Ave, Pine Ave, Bailey Ct, Highway 206, Devils Canyon Rd, Cloudland Truck Trail, Cloudland Cutoff, Hill Dr, W 54th St, E Hill Dr, Bonita Vista Dr, Sterling Ave, Argyle Ave, E Marshall Blvd, Rockford Ave, Lynwood Dr, La Praix St, Orchid Dr, Denair Ave, Highland Ave, Orchard Rd, Arroyo Vista Dr, Church St, Greensport Rd, Florida St, Garnet St, Nice Ave, Crafton Ave, 5th Ave, Walnut St, 6th Ave, S Wabash Ave, E Citrus Ave, N Church St, Southern California Regional Rail A, Tennessee St, Highway 10, California St, E Washington St, and S Barton Rd. The 28th district takes in the north side of the cities of Upland and Rancho Cucamonga and the census-designated places San Antonio Heights, Lytle Creek, and Wrightwood.