Head and body length of T. talpoides is between 115-305 mm, tail length is 40-95 mm. Weights range from 45-545 grams. The soft, short fur is nearly uniform in color and covers the entire body, except for the tip of the tail. Variations of color are from almost black, gray, brown and almost white. Underparts are only slightly lighter. The body is robust with short legs. The eyes and ears are small, and unlike most other geomydes, the incisors of Thomomys usually lack frontal grooves. T. talpoides has long front claws, enabling it to dig an extensive system of burrows consisting of deep permanent galleries and shallow feeding tunnels.

T. talpoides spends most of its life underground. Galleries can be 1-3 meters below the surface and contain several nesting and storage chambers which are about 200-250 mm in diameter. These galleries are centralized, with feeding tunnels radiating from them. They range from 50-460 mm deep and are about 50 mm in diameter. Tunnel entrances are evident from the fan-shaped mounds of dirt surrounding the holes. These entrances are usually blocked with a mound of dirt, and the Pocket gopher seldom strays far from the entrance during the day. They are somewhat more active at night, venturing out above ground. T. talpoides is active year round and often build passages through the snow, lining them with excavated earth.

Their diet consists of roots, bulbs, leaves, cultivated crops, and other vegetation. If possible, they will burrow beneath a plant, chew off the roots and pull it through the ground by the stem. Food is cut into small pieces and stored in the fur lined cheek pouches for transportation. Pocket gophers do not drink water, apparently getting sufficient moisture from the vegetable matter.

T. talpoides is primarily solitary, individuals avoiding each other in the wild. During mating season, males are allowed to enter the burrows of females. Female Pocket gophers are monestrous, producing one litter of 1-10 young each year. Gestation is 18 days, and the babies remain in their mother's burrow for about 2 months, then disperse. They reach adult weight at about 5-6 months and breed the following season. Life expectancy for T. talpoides is about 2 years in the wild, as they are prey for coyotes, badgers, and foxes.

Though they are often accused of damaging grasslands, their burrowing actually benefits the ecosystem by aerating the soil, and storing plant matter underground enriches the soil by creating humus. Their tunnels also provide a storage system for water when snow melts into the burrows.

T. talpoides is found in S British Columbia to C Alberta and SW Manitoba (Canada), south to C South Dakota and N New Mexico, N Arizona, N Nevada, and NE California (USA).