California State Route 39

State Route 39 (SR 39) is a state highway in the U.S. state of California that travels through Orange and Los Angeles counties. Its southern terminus is at Pacific Coast Highway (SR 1), in Huntington Beach. SR 39's northern terminus is at Islip Saddle on Angeles Crest Highway (SR 2) in the Angeles National Forest, but its northernmost 4.5-mile (7.2 km) segment (including the connection with SR 2) has been closed to public highway traffic since 1978 due to a massive mud and rockslide.

Officially, the highway is broken into pieces. Caltrans has not adopted or signed the segment between La Habra and West Covina. Caltrans has also relinquished control of segments of SR 39 within the cities of Anaheim in 2024, Buena Park in 2013, Azusa by 2010, Covina by 2010, and West Covina by 2013, although some maps and signs may still mark SR 39 as continuous through these cities. Since 2001, a portion of SR 39 that runs through the city of Stanton has also been considered for relinquishment to the city.

Major places of interest along SR 39 are Knott's Berry Farm, an amusement park; Adventure City, another amusement park targeted for children; Huntington Beach, a local beach; a Medieval Times location; the Buena Park Auto Center; and the Westridge Golf Course in La Habra.