It runs from North Portal at the Canada–United States border north-west to Moose Jaw at Highway 1.

Over the last number of years, multiple projects have been completed to improve traffic flow and to make the highway safer.

Groups have been calling for the corridor of Highways 39 and 6 from the U.S. border to Regina to be twinned to improve safety, trade, and traffic flow.

[10][11] Highway 39 begins at the Portal–North Portal Border Crossing, which has Saskatchewan's only duty-free shop.

The cairn commemorates a North-West Mounted Police camp from the 1874 Great March West.

The actual camp was located nearby at the mouth of Short Creek on the Souris River near Roche Percee.

[15] Just east of Roche Percee are two arches created by limestone rocks upon which historic animals, and initials are carved.

Along the way, the highway provides access to many small communities, such as Hitchcock, Macoun,[22] Midale, Halbrite,[23] and Ralph.

[26] Weyburn is at the crossroads of three major highways — 35, 39, and 13[27][28] and is near the upper delta of the 760-kilometre (470 mi) long Souris River.

"Extensive flood control programs have created reservoirs, parks and waterfowl centres along the Souris River.

"[27][29] Notable points of interest in Weyburn accessible from Highway 39 include the Soo Line Historical Museum,[30][31] Tommy Douglas statue, Weyburn Heritage Village,[32] Water Tower,[33] River Park Campground,[34] and the site of the former Saskatchewan Hospital.

Communities along the stretch of highway from Weyburn to Corinne include McTaggart, Yellow Grass, Lang, and Milestone.

Rouleau was the host town for the popular Canadian sitcom, Corner Gas, which aired from 2004 to 2009.

'Highways 6 and 39 are very important to Saskatchewan — serving as tourism links and major north–south trade corridors to the U.S.,' former NDP Highways and Transportation Minister Maynard Sonntag had said in 2004.

[40] As late as 1955 though, there were still right angle segment of the highway near Corinne as well as south of Estevan to North Portal.

[42] However, the paved surface fell into disrepair within a few years; a Leader-Post reporter wrote in 1953 that "practically the entire road, from North Portal through to Corinne is just a mass of large gaping potholes, ruts, and cracks, and in some places the hard surface is gone completely.

[42][45] In 2008, a trade group called the Soo Line Corridor Association advocated twinning much of Highway 39 and part of Highway 6 to create a continuous twinned corridor stretching from Regina to North Portal to boost Saskatchewan's trade with the United States.