The Santa Ana Freeway is one of the principal freeways in Southern California, connecting Los Angeles and its southeastern suburbs including the freeway's namesake, the city of Santa Ana. The freeway begins at its junction with the San Diego Freeway, called the El Toro Y, in Irvine, signed as I-5. From there, it generally goes southeast to northwest to the East Los Angeles Interchange, where it takes the designation of U.S. Route 101. It then proceeds northwest to the Four Level Interchange in downtown Los Angeles. Formerly, the entirety of the route was marked as US 101 until the 1964 highway renumbering, which truncated US 101 to the East Los Angeles Interchange and designated the rest of the freeway as I-5. North of the East Los Angeles Interchange complex, I-5 follows the Golden State Freeway. South of the El Toro Y, I-5 takes on the San Diego Freeway name from I-405. An abundance of landmarks, most importantly Disneyland and Angel Stadium of Anaheim, along the Orange County portion of its route combines with a severe bottleneck beginning at the Los Angeles County line to make it one of the most congested freeways in Southern California. The infamously busy intersection of the Santa Ana, Garden Grove, and Orange freeways in southwestern Orange is nicknamed the Orange Crush. The freeway is officially defined as Routes 101 and 5 from Route 110 to Route 405.
History
The Santa Ana Freeway is a bypass of the original state highway from Los Angeles to Santa Ana, which passed through Whittier and mostly became SR 72 in the 1964 renumbering. Southeast of Santa Ana, this earlier highway, added to the statehighway system in 1910 as Route 2, generally followed the present freeway from Tustin past East Irvine to El Toro. This route was marked as part of US 101 in 1928. In 1933, the state legislature added a number of routes to the state highway system, including two that later formed parts of the Santa Ana Freeway. Route 166 began at the new Route 172, at the corner of Indiana and Third Streets, and headed south on Indiana Street and east and southeast on Mines Avenue and Anaheim-Telegraph Road to Route 171 at the intersection with Los Nietos Road near Santa Fe Springs. Route 174 began at Route 60 in what now is known as Westchester and followed Manchester Avenue and Firestone Boulevard to Route 2 in southern Anaheim. A second piece began further southeast on Route 2, where it turned east on Chapman Avenue, and followed the shorter Santa Ana Boulevard diagonally to Route 2 in northern Santa Ana. In 1934, Route 166, except on Indiana Street, was marked as part of Sign Route 6, and the entire length of Route 174 became Sign Route 10. A U.S. Route 101 Bypass was created by 1941, beginning at the intersection of Routes 166 and 2, and following Routes 166 and 174 to Route 2 in Anaheim. The connection between Routes 166 and 174 was made via Route 168. This resulted in SR 10 being truncated further, to the intersection of Firestone and Rosemead Boulevards, though SR 26 continued to extend east on Routes 166 and 171 to Buena Park. A freeway connecting downtown Los Angeles with Orange County was planned by 1939, and was included in A Transit Program for the Los Angeles Metropolitan Area, published that year by the Metropolitan Transportation Engineering Board. To allow for its construction by the state, the definition of Route 166 was modified in 1941, changing the southeast end to Route 174 near Norwalk; at the same time, the northernmost piece was changed from Indiana Street to Downey Road. The entire Santa Ana Freeway began construction in 1947 and completed in 1956. Originally it was signed as US 101 before the segment of 101 between the East Los Angeles Interchange and the United States–Mexico border in San Ysidro, California was decommissioned in favor of Interstate 5. It was approved as a chargeable interstate in 1961. The Santa Ana Freeway and also portions of San Diego Freeway south of El Toro Y went up changing the U.S. 101 signs to Interstate 5 in 1964, including full length of Golden State Freeway which was originally signed as US 99.
Former Interstate 105
From 1964 to 1968, the I-105 designation was used on a stretch of road linking I-5/I-10, US 101, and SR 10 north of downtown Los Angeles, now known as the East Los Angeles Interchange. In 1968, this I-105 was decommissioned, and that portion of the Santa Ana Freeway was folded into US 101.
