Historic US 99 Guide

Los Angeles Area: East

Whitewater River near Palm Springs This bridge also carried US 60 and US 70 and was in operation from 1925 to 1952 when it was replaced by the freeway. Mt San Jacinto is in the background.

Pomona and San Gabriel Valleys

The San Gabriel and Pomona Valleys were mostly farmland until after World War II when they started to be supplanted by suburban housing developments. The Pomona Valley and the city that shares its name were named for the Roman goddess of the harvest Pomona. San Gabriel, both city and valley, is named for the mission, San Gabriel Arcangel which was located east of downtown Los Angeles.

After Valley Blvd rejoins the freeway just to the east of the interchange with I-15, the current freeway was paved over its grade to the west. From this point west, US 99 took several different alignments, some of which I won't be able to document at this time. The section of highway from Valley Blvd to the Holt Ave exit dates back to at least 1939. This section was upgraded to freeway status between 1953 and 1955. Before 1953, US 99 followed Holt Blvd to the current "Kellogg Hill" interchange, what is now the I-210, SR-57/10 interchange. The current freeway bypassed this segment between 1953-55 and was widened to the modern eight lanes between 1969 and 1975.

The SR-71 overcrossing marks the location where US 60 rejoined Routes 99 and 70 after the freeway was built. However, the modern SR-71 / I-10 separation was built in 1971, completely replacing the Holt Ave separation, which is what US 60 followed. It is also here that the pre-1953 alignment of US 99 along Holt Ave merges into the freeway. Previously, Holt Ave. followed what is now the freeway to the west. Beyond Kellogg Hill there are several alignments of US 99 buried under the freeway.

One of the oldest alignments follows Covina Hills Road, slightly to the north. A 1935 USGS map shows US 60, US 70, US 99 following Covina Hills Road, with a new road following the alignment of I-10 being built. The new alignment was called Garvey Ave and it lasted until 1956, when the freeway was paved over it and Garvey Ave was relegated to the status of frontage road. This continues to the Garvey Ave separation, just west of the San Gabriel River.

US 99 followed Garvey Ave to what was then Ramona Blvd which is now under I-10 east of Los Angeles. There is an interesting old concrete arch bridge which dates from the 1932 that creates the separation of Garvey Ave and Monterey Pass Rd/Fremont Ave in Monterey Park. Just beyond this, Garvey Ave merges with the I-10 freeway. The sharp curve along Garvey Ave just to the east of the intersection with the I-10 frontage road was part of the original alignment. Before the freeway, it was a left turn onto Ramona Blvd., which has since been covered by the freeway. In 1956, this section of Garvey Ave was bypassed to Rosemead Blvd, SR-19. However, the freeway from the east of the current junction with I-710 to SR-19 was built earlier, between 1951-53. Consequently, between 1953 and 1956, Rosemead Blvd was signed as US 60 / US 70 / US 99 as well as SR-19 from Garvey Ave to the intersection with the freeway.

Los Angeles

In 1943 part of US 99 was upgraded to a freeway, or a parkway as it was called, as a wartime project. The parkway (freeway) followed the current alignment of I-10 between the intersection with Garvey Ave and the intersection with US 101. This was known as the " Ramona Parkway," since it was built over Ramona Blvd. Previously, US 99 followed Ramona Blvd to Marengo St. and did not intersect US 101. However, US 60, US 70 did go to US 101 which was Macy St. (now called Chavez Ave.) This intersection has been modified by the freeway, which did carry US 99 after 1947, so the original is no longer visible. The western termini of US 60 and US 70 were located at this intersection. After the construction of the Ramona Parkway (now I-10) and the Santa Ana Parkway, US 101, in 1947, the intersection was a "Y" style interchange which was almost as advanced for the time as the Four Level Interchange to the west. A major feature of this interchange was a sizeable modern style connector bridge which connected US 99 north to US 101 south. This bridge was in place until 1995 when it was demolished for earthquake safety reasons. The construction of the Golden State Fwy. to the east in 1960 made this connector obsolete.

Before the construction of the present freeways in the area US 99 diverged from US 60 and US 70 at Marengo St., heading to the north. This intersection has also been modified by the construction of the freeway and the closest approximation to its location is where Marengo St. intersects Soto St. US 99 followed Marengo St., then Daly St. to Ave 26. It went left on Ave 26 and followed it to the intersection with San Fernando Rd. Before 1940, US 99 intersected US 6 at Figueroa St., then its successor, the Pasadena Fwy.

After the freeways were built, US 99 was co-signed with US 101 from the interchange to the east of Los Angeles to the Four Level Interchange, going through the "Downtown Slot." The Four Level is, of course, a very historic interchange. It was the first of its kind in the world and its design was so good that many modern incarnations abound, granted that they are much larger and much safer. For example, the I-8 / I-805 intersection in Mission Valley near San Diego is the epitome of this design, with I-805 crossing Mission Valley and I-8 over a 3/4 mile long bridge which is over 200 feet tall! Yet it was inspired by the Four Level. This interchange also marks the convergence of several important highways, namely US 6, US 66, US 99 and US 101. It also appears for a time to have been the western terminus of US 60 and US 70, two major transcontinental highways.

US 99 went north along the Pasadena Fwy. along with US 6 and US 66 making for a unique signing situation. It left the Pasadena Fwy., along with US 6 at the Ave 26 exit where it rejoined its old alignment. US 99 remained co-signed with US 6 for about 20 miles to the north end of the San Fernando Valley. US 99 continued north along San Fernando Rd. all the way north through the San Fernando Valley.

The construction of the Golden State Freeway gradually bypassed the San Fernando Road alignment. By 1962, US 99 was transferred to the new freeway and was signed with I-5, its successor. Even though US 99 ceased to exist as a legislative highway in 1964, signs designating it remained on the Golden State Fwy. until the end of the 1960s.

This section of the guide ends at the intersection of US 99 and US 6, which is now the I-5/SR-14 interchange.

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