Major features include the Double H, Montana and Bilk Creek mountains as well as the southern Trout Creek Range and two valleys, Kings and Quinn River. Elevations range from 4,100 feet above sea level to 8,300 feet. The unit offers hunting for mule deer, antelope and California bighorn sheep.

This area has steep slopes, sheer cliffs, deep and shallow drainages, rolling hills and desert flats. Montana and Double H Mountains have the steepest elevation changes, while the Bilk Creek Mountains and the Trout Creek Range are like several other ranges in the Intermountain west with toe slopes, well-defined drainages, ridges, swales and peaks. Elevations are lowest in the south and highest at the south end of the Trout Creek Range in the northern part of the unit.

Much of Unit 31 is public land, but the valleys of Kings River and Quinn River are a mix of public and private land. Vehicles can reach parts of the Bilk Creek Mountains and the Trout Creek Range, but hunters must hike to reach much of the mountain land. Public vehicle access is available along the western rims and eastern fingers of the Montana and Double H mountains. Some areas are only accessible by foot. Lower elevations feature a network of good to well-maintained roads. Most are accessible to the public, but some are posted as private. U.S. Route 95 is the eastern border of the unit, State Route 140 is the southern and western boundary. State Route 293 (Kings River Road) provides access to Kings River Valley.

The upper parts of the Bilk Creek Mountains and Trout Creek Range are covered with desert brush, aspen and mountain mahogany. Middle elevations are composed of desert brush and scrub with scattered serviceberry bushes. Desert scrub and playa/alkali flats are what make up most of the lower elevations. In 2012, range fire burned about 215,000 acres including much mule deer habitat in the Bilk Creek, Trout Creek and Montana mountains. Some of acreage is expected to recover well over the next 10-15 years, particularly in the upper elevations. Other areas have become inundated with cheatgrass and will struggle to recover for several years.

Lodging, fuel and supplies are available at Denio Junction in the northwestern corner, McDermitt in the northeastern corner and Winnemucca, just south of the unit. Hunters can camp by dirt roads, which is allowed on almost all public land.