Colorado State Highway 121
|Maintained by CDOT|
|Length||30.425 mi (48.964 km)|
|South end||Waterton Road near Littleton|
|North end||US 287 in Broomfield|
|Counties||Jefferson, Denver, Broomfield|
State Highway 121 (SH 121) is a 30.425 mile (48.96 km) long state highway in the U.S. state of Colorado. SH 121's southern terminus is at Waterton Road near Littleton, and the northern terminus is at U.S. Route 287 (US 287) in Broomfield.
The route, also known as Wadsworth Boulevard, Wadsworth Bypass, and Wadsworth Parkway, starts at a junction with Waterton Road in unincorporated Jefferson County (near Littleton and at the entrance to the main plant of Lockheed Martin Space Systems) and ends at the junction of U.S. Route 36, U.S. Route 287, and State Highway 128 in Broomfield at a trumpet interchange. State Highway 121 passes through portions of southwest Denver County.
The name Wadsworth comes from Benjamin Franklin Wadsworth, one of the founders and first postmaster of Arvada. In northwest Arvada, Wadsworth Boulevard passes over Hackberry Hill at the site where a landmark hackberry tree, for which the hill was named, stood before it was cut down to make room for the highway in 1937. 
|Jefferson||||0.00||0.00||Waterton Road||Southern terminus|
|||4.41||7.10||SH 470||C-470 Exit 13; Interchange;|
|Lakewood||7.49||12.05||US 285 (Hampden Avenue)||Interchange|
|9.06||14.58||SH 8 west (Morrison Road)||Eastern terminus of SH-8|
|12.44||20.02||US 6 (Sixth Avenue)||Interchange|
|13.59||21.87||US 40 / I-70 BL (Colfax Avenue)|
|Arvada||16.79||27.02||I-70 / I-76 east – Denver, Fort Morgan, Grand Junction||I-76 exit 1a; I-70 exit 269a|
|City and County of Broomfield||25.82||41.55||SH 128 (Interlocken Loop)|
|26.02||41.88||US 36 – Denver, Boulder||Interchange|
|26.42||42.52||US 287||Interchange; Northern terminus, Road continues north as US-287.|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi|
- "Segment list for SH 121". Retrieved 2007-05-12.[permanent dead link]
- "Jefferson County, Colorado Place Names Directory". Retrieved 2012-03-23.