Colorado 121 follows South Platte Canyon Road and Wadsworth Boulevard (also called Wadsworth Parkway in some areas) from the entrance to the Lockheed Martin plant at the south end of Chatfield State Park north to U.S. 287 in Broomfield near the interchange with U.S. 36 (Denver-Boulder Turnpike) and Colorado 128. The southern end of the route is near the Platte Canyon Reservoir naer Kassler Road. The entire route is over 30 miles long, but most of it is four to six lanes wide and serves suburban locations.
Colorado 121 North
This picture shows northbound Colorado 121 at Junction U.S. 40, Colfax Avenue. Colfax Avenue is also known as Business Loop I-70, but the business loop designation is not normally shown on signage such as this assembly. Photo taken 02/02/02.
Northbound Colorado 121/Wadsworth Boulevard approaching Junction Interstate 70 and 76. No, this is not in Pennsylvania. The upcoming interchange connects Colorado 121 with westbound and eastbound Interstate 70 and also with north-eastbound Interstate 76. The upcoming ramp from northbound Colorado 121 connects to both Interstate 70 and Interstate 76. Note the state name appears in both shields. Photo taken 02/02/02.
Northbound Colorado 121/Wadsworth Boulevard ramp to Eastbound Interstates 70 and 76. This marks the western terminus of the western Interstate 76. The second ramp leads to westbound Interstate 70 (just beyond the overpass in the distance). This is a major interchange, and a large shopping mall with various amenities just northwest of this interchange contributes to the large traffic flow in this area. Photo taken 02/02/02.
Colorado 121 South
Colorado 121 begins at a trumpet interchange with U.S. 287 in Broomfield. From there, it immediately interchanges with U.S. 36, the Denver-Boulder Turnpike. Only a short distance south of the turnpike, Colorado 121 meets Colorado 128 at 120th Avenue. Colorado 128 travels west to serve the Jefferson County Airport (even though the entrance to the airport is from Boulder County), passing by the Rocky Flats (a former Department of Energy facility that is now a clean-up site), and then ending at Colorado 93 (Foothills Road). Photo taken 08/28/04.
Much of Colorado 121 near Broomfield and Westmister in Jefferson County has been recently reconstructed. The highway is concrete, and there are only sporadic traffic signals and congestion along the route. The Jefferson County Airport is visible to the west of Colorado 121, and views of Denver are afforded in the distance. This is probably the most rural section of Colorado 121, but it is heavily traveled by people making the connection from U.S. 36 and U.S. 287 south to western areas of Denver, as well as Arvada, Wheat Ridge, and Lakewood. This is part of a "short cut" between Boulder and Interstate 70 that does not involve Interstate 25, Colorado 93, or Colorado 119. Photo taken 08/28/04.
By the time we get to the interchange with Interstate 70 and Interstate 76, Colorado 121 has entered suburbia. The concrete highway (Wadsworth Parkway) changes into Wadsworth Boulevard as it enters Arvada. Near the freeway interchange, a variety of large shopping complexes, movie theaters, and restaurants have sprung up, forcing more traffic onto an already burdened area. It is neat to see Interstate 70 and Interstate 76 on the same signs; there is access to Interstate 70 west via the first ramp, while a flyover makes the connection from southbound Colorado 121 to eastbound Interstate 70 and eastbound Interstate 76. The flyover ramp forks to serve both routes. Photo taken 08/28/04.
The right lane connects first to westbound Interstate 70, then offers a connection to Interstate 70-76 eastbound. Use Interstate 70 west to Wheat Ridge, Golden, Idaho Springs, and most mountain destinations (including ski resorts). Interstate 70 east travels to downtown Denver, then begins the long journey to Kansas. Interstate 76 avoids downtown Denver, then travels along the South Platte River through northeastern Colorado before joining Interstate 80 in Nebraska. After passing this freeway interchange, Colorado 121 leaves Arvada and enters Wheat Ridge. Photo taken 08/28/04.
Continuing south, Colorado 121 leaves Wheat Ridge and enters Lakewood just prior to the intersection with Colfax Avenue (Business Loop I-70 and U.S. 40). The business route follows one of the longest continuous city streets in the country, Colfax Avenue, traveling west to Golden and east to downtown Denver and the state capitol. Photo taken 08/28/04.
A mile or so south of there, Colorado 121/Wadsworth Boulevard meets U.S. 6, Sixth Avenue. This freeway provides a fast alternate route between Golden and Denver, avoiding Colfax Avenue and Interstate 70. Sixth Avenue was a city street that was upgraded to an expressway in the late 1950s, and it was subsequently brought to freeway standards in stages thereafter. Even so, U.S. 6 is not up to Interstate standards. Photo taken 08/28/04.