Connecticut Route 21

Route 21
Map of Windham County in northeastern Connecticut with Route 21 highlighted in red
Route information
Maintained by CTDOT
Length	5.67 mi[1] (9.12 km)
Existed	1944–present
Major junctions
South end	Route 12 in Killingly
Major intersections	US 44 in East Putnam
North end	Route 193 in Thompson
Location
Country	United States
State	Connecticut
Counties	Windham
Highway system
Connecticut State Highway System Interstate US State SSR SR Scenic
← Route 20 → Route 22

Route 21 is a 5.67-mile (9.12 km) state highway in rural northeastern Connecticut. It extends from Route 12 in Killingly to Route 193 in Thompson. It serves as an alternate to Route 12 in the town of Putnam.