Colorado State Highway 257

State Highway 257 (SH 257) is an 18.478 mile state highway in the Front Range in Weld County, Colorado, United States, connecting SH 60 in Milliken with SH 14 in northwestern Severance.

Route description
SH 257 begins at a junction with SH 60 and County Road 21 (CR 21) northwest of central Milliken. It then heads northward, crossing the Big Thompson River, a tributary of the South Platte River, before entering western Greeley.

In Greeley, SH 257 has two interchanges: one with U.S. Route 34 (US 34) and one with U.S. Route 34 Business (US 34 Bus.). Because the junction with US 34 Bus. is so close to its terminus, the two interchanges are just 0.3 mi apart. Both are diamond interchanges, but only the US 34 intersection has complete access.

SH 257 then heads northwards before turning northwest, crossing over the Cache la Poudre River and entering Windsor. It abruptly turns west and begins a concurrency with intersects Colorado State Highway 392 (SH 392) along Main Street. About 1 mi later, SH 257 turns back northward along 7th Street, ending its concurrency with SH 392. SH 257 then heads north to SH 14, where it terminates at the town limits of northwestern Severance.

History
The route was established in 1939 with several differences. The route went north to Windsor from Milliken, then turning west to Colorado State Highway 185 (SH 185). SH 185 was then deleted and replaced with Interstate 25 (I‑25), and SH 257 was readjusted so that it went north to SH 14. The route was paved by 1954. A spur south of Windsor was eliminated a year later. The interchanges at US 24 and US 34 Bus. were built in 1998.

In November 2009, a new traffic signal was installed at the intersection with Garden Drive in Windsor. The construction cost about $350,000.

Related route
State Highway 257 Spur (SH 257 Spur) was a 1.1 mi state highway business route in Weld County. It was a spur east from SH 257 to US 34 Bus. west of Greeley. The road no longer connects to SH 257 since it was barricaded off.