Alberta Provincial Highway No. 21A, commonly referred to as Highway 21A, was the designation of two former spur routes of Highway 21 in Alberta, Canada.
| Southern segment | ||||
|---|---|---|---|---|
| Length | 33 km[1] (21 mi) | |||
| South end |  Hwy 9 in Beiseker | |||
| North end |  Hwy 21 near Carbon | |||
| Northern segment | ||||
| Length | 5 km[2] (3.1 mi) | |||
| West end | Hwy 21 near Nevis | |||
| East end |  Hwy 12 near Nevis | |||
| Location | ||||
| Country | Canada | |||
| Province | Alberta | |||
| Specialized and rural municipalities | Rocky View County, Kneehill County, County of Stettler No. 6 | |||
| Villages | Beiseker, Acme | |||
| Highway system | ||||
| ||||
Southern segment
The southern section of Highway 21A was a 33 km (21 mi) highway which started at Highway 9 in the Village of Beiseker and traveled north for 13 km (8 mi) to the Village of Acme and then turned east for 20 km (12 mi) to Highway 21, 8 km (5 mi) northeast of the Village of Carbon.[1] It was established in 1958/59 when Highway 21 was realigned from Beiseker to Highway 1 (Trans-Canada Highway) east of Strathmore.[3][4] Highway 21A was renumbered to Highway 26 in 1962/63,[5][6] and in 1972/73 the north-south section became Highway 806 while the east-west section became Highway 575.[7][8]
Northern segment
The northern section of Highway 21A was a 5 km (3 mi) highway that connected Highway 21 with Highway 12 near the Hamlet of Nevis.[2] In the early-1990s, Highway 11 was extended east from Highway 815 near Joffre to Highway 21; when construction was completed, Highway 21A became part of Highway 11.[9][10]