Throughout the northern two-thirds of the United States and southern Canada, the little brown myotis (insect eating bat), and big brown bat are the most likely species to be encountered in bat houses. In the southern United States, Mexican freetailed and evening bats are most common. Almost any bat that will roost in buildings or under bridges is a candidate for a bat house. These species have been documented as bat house users:

Big Brown Bat, Eptesicus Fuscus
Most of the United States and Canada, except for extreme southern Florida and south and central Texas. Rears young in tree hollows, buildings and bat houses. Hibernates in caves, abandoned mines and buildings. Frequent bat house users, they have overwintered in bat houses from Texas to New York.

Cave Myotis, Myotis Velifer
Southern California and Arizona into central Texas, Oklahoma and south-central Kansas. Forms large nursery colonies in caves and rears young in smaller groups in buildings. The eastern subspecies hibernates in caves, but the winter habitat of the western subspecies is unknown.   Shares bat houses with Mexican free-tailed bats in Texas.

Eastern Pipistrelle, Pipistrellus Subflavus
Eastern North America into Canada, except northern Maine, and south to Texas and central Florida. Little is known about summer roosts; sometimes rears young in tree foliage or in buildings. Several pipistrelles twice reported in bat houses. Hibernates in caves.

Evening Bat, Nycticeius Humeralis
East of the Appalachians, ranges from southern Pennsylvania to Florida; west of the mountains, from southern Michigan and Wisconsin into Nebraska and south into Texas. Rears young in buildings, tree cavities and bat houses. Nursery colonies often share roosts with Mexican freetailed bats. Winter habitat unknown.

Indiana Myotis, Myotis Sodalis
Endangered species associated mainly with forests and limestone caves in the eastern United States. Maternity colonies mainly roost beneath loose bark. Most hibernate in about eight caves and mines in three states. Occasionally uses buildings, bridges and bat houses;  reported in bat houses in Illinois, Indiana and Pennsylvania.

Little Brown Myotis, Myotis Lucifugus
Wooded areas throughout most of Canada and the northern half of the United States, except desert and arid areas. A few isolated populations farther south. Rears young in tree hollows, buildings, rock crevices and bat houses. Travels to nearest suitable cave or abandoned mine for hibernation. This is the species that most commonly occupies bat houses.

Long-eared myotis, Myotis evotis
Primarily in forests of southwestern Canada and the western United States. Often lives alone or in small groups; females form small maternity colonies in summer. Roosts in hollow trees, under bark, in cliff crevices, caves, mines and abandoned buildings. Confirmed bat house user in Washington. Winter habitat unknown.

Northern Myotis, Myotis Septentrionalis
Upper Midwest, eastern, and some southern states and into Canada. Summer roosts vary.  Northern myotis have been found beneath tree bark, in buildings and in caves. Little is known about nursery colonies, but small numbers have been found rearing young beneath tree bark, in buildings and in bat houses. Hibernates in rock crevices, caves and mines.

Mexican Free-tailed Bat, Tadarida Brasiliensis
Common in southern and southwestern United States and north to Nebraska, Colorado, Utah, Nevada and Oregon. Rears young in caves, in buildings, under bridges and in bat houses.  Frequent bat house user. Migrates to overwinter in caves of Mexico and Central America, but nonmigratory in the southeastern United States and West Coast. Active year-round.

Pallas’s Mastiff Bat, Molossus Molossus
In the United States, found in buildings in the Florida Keys only. Throughout the Caribbean, northern Mexico, Central America and northern South America, its roosts include hollow trees, palm fronds, rock crevices, caves, bridges, culverts and buildings. Uses bat houses year-round in Cayman Islands and Puerto Rico.

Pallid Bat, Antrozous Pallidus
Western and southwestern United States and extreme south-central British Columbia, mostly in arid areas. Found in rock crevices, buildings, under bridges and in bat houses. Winter habitat unknown, presumed to hibernate locally in deep rock crevices.

Myotis Austroriparius
Mostly restricted to Gulf Coast states. Rears young in caves, tree hollows and buildings.  Often nonmigratory, hibernates in caves in its northern range and sometimes in tree hollows or buildings farther south. Confirmed bat house user in Florida and Georgia; believed to use bat houses in other Gulf states.

Wagner’s Bonneted Bat, Eumops glaucinus
Southern Florida only. Extremely rare, seen only a handful of times since the 1960s. Uses buildings with Spanish tile roofs, as well as palm fronds and woodpecker holes. A maternity colony with 11 individuals was confirmed using a bat house with a 11/2-inch chamber in southwest Florida.

Yuma Myotis, Myotis Yumanensis
Southern British Columbia, Washington, Idaho, Oregon, California, Arizona, extreme western Nevada, eastern Utah, southern Wyoming to western New Mexico. Restricted to areas near water. Rears young in caves, in buildings, under bridges and in bat houses. Winter habitat unknown. Lives in bat houses from Arizona to British Columbia.