The generic name, Microtus, derives from the Greek words μικρός meaning "small" + οὖς "ear".

[4] The type specimen was a female collected by Vernon Orlando Bailey in the Black Hills at an altitude around 5,500 ft (1,700 m) near Custer, South Dakota, on July 19, 1887.

[2] The Coronation Island vole, once considered to be a separate species, is now believed to be a subspecies.

[3] The tail is bicolored and extends greater than one-third the animal's total length.

[5] Merriam also noted some "peculiarities", not otherwise specified, in the original description, which distinguish the long-tailed vole from other species known in the late 1800s.

The basal shaft is dumb-bell shaped in cross section and tapers to a blunt point at the end.

The shaft is broad in dimension and connects via cartilaginous linkages to three lateral segments.

[4] Long-tailed voles do not usually have the hip glands, which are found in other members of the genus Microtus.

[10] As such, collected fossils are identified based on probabilities of occurrence within the geographic range or with other associated species.

[10] These animals are found in a wide variety of habitats, including alpine meadows and shrubby areas, often near streams.

[7] They may live in dense forests of conifers or in more arid, sagebrush type of habitats.

[12] In the Malheur National Wildlife Refuge, they reside among marshes of hardstem bullrush (Schoenoplectus acutus), cattail (Typha latifolia), baltic rush (Juncus balticus), and sedges (Carex sp.).

[7] Near the southern and eastern limits of the geographic range, they tend to reside at higher elevations.

[7] The range extends south through the western Canadian provinces of Alberta, British Columbia, Northwest Territories, and Yukon.

[7] The breeding season begins in May and extends through September or October, depending on location.

[10] Long-tailed vole parents will respond to ultrasonic cries made by the newborns in distress.

[12] Long-tailed vole populations can fluctuate widely over a period of time within a given locale.

Long-tailed voles are common and have a very widespread geographic distribution, with a number of protected areas within the range.