The following is a press release from Missoula Parks and Recreation:

 

The return of winter will bring Mount Jumbo’s own special elk herd back to its traditional winter range.When winter snows deplete forage at higher elevations, about 75 elk move to Jumbo’s lower slopes to feed. To help increase the elk herd’s chance for winter survival, critical areas of the mountain are closed seasonally to recreational use. Mount Jumbo's North Zone, from the Saddle Road to the north, is closed
from December 1 until May 1. The South Zone, from the Saddle Road south to I-90, is closed from December 1 to March 15. Maps and more information are available here

The Saddle Road is located at the north end of Lincoln Hills Drive.
Several trails on Mount Jumbo are open all year, including the U.S. West road above I-90 and the “L” trail, both of which are accessible at the Cherry Street trailhead. Short trail sections beginning at Hidden
Trail in East Missoula and Marshall Canyon will also remain open. Dogs must be leashed on Mount Jumbo during the winter closure. The road linking Upper Lincoln Hills Drive with Tamarack Street and the 40 acres
below the road are also open all year. Winter hikers and their canine companions can enjoy the numerous trails, scenic views and varied
terrain on the North Hills, Mount Sentinel, Rattlesnake Greenway; and in the Pattee Canyon, Blue Mountain and Rattlesnake Recreation Areas. The new Parks and Trails map, available at Currents Aquatics Center
and local retailers, features detailed maps of open space trails. The map is priced at $4.