 I-5 then intersects SR 91, passes through Buena Park and crosses into Los Angeles County.After crossing the county line, I-5 goes through several cities southeast of Los Angeles, including La Mirada, Santa Fe Springs, and Norwalk.In Downey, I-5 intersects I-605, which serves as a north–south connector route between the cities east of Los Angeles, including those in the San Gabriel Valley.