Partners in Flight estimates a global population of 4 million, while the American Bird Conservancy estimates that 1.5 million individuals exist.

During the breeding season 82% of the population can be found in Canada and 18% in the United States.
In Canada the summer range extends from southeastern Yukon to Nova Scotia.
In the United States the range extends from northern Minnesota to northern Pennsylvania, west to Long Island of New York.
It also nests in the high Appalachians as far south as Georgia.
In winter the Canada warbler's range extends from Guyana to northwestern Bolivia around the northern and western side of the Andean crest.

In both summer and winter seasons the Canada warbler inhabits moist thickets.
During the breeding season the bird "nests in riparian thickets, brushy ravines, forest bogs, etc.
at a wide range of elevations and across a variety of forest types.
In the northwestern parts of its range it frequents aspen forests; in the center of the range, it is found in forested wetlands and swamps; and in the south it occupies montane rhododendron thickets."

In the winter it prefers mid- and upper-elevation habitats.
In northern Minnesota a study found that Canada warblers inhabited the shrub-forest edge, rather than marture forests or open fields with shrub.
In New England the Canada warbler was found to be "disturbance specialists" moving into patches of forests recovering from wind throw or timber removal.
Because of its preference for low-height foraging in deciduous forests, it may be bounded at higher elevations as suitable habitat disappears and suffer competition from the black-throated blue warbler which prefers similar habitats.

Two accidentals have been observed in Europe.
The first a moribund male caught in Sandgerði, Iceland on September 29, 1973.
The second was a first winter, probably female observed for five days in October 2006 in County Clare, Ireland.

The age at which the young leave the nest is not known.
Once independent they spend almost all their time in the understory, on the ground or in bushes.
The post-juvenile bird undergoes a partial moult involving all body feathres and wing coverlets.
This may be completed before the first migration.

The oldest known specimen was a male found in Quebec in 1982 at least 8 years old, having been banded in 1975.
Partners in Flight estimates a global population of 4 million, while the American Bird Conservancy estimates that 1.5 million individuals exist.
During the breeding season 82% of the population can be found in Canada and 18% in the United States. In Canada the summer range extends from southeastern Yukon to Nova Scotia. In the United States the range extends from northern Minnesota to northern Pennsylvania, west to Long Island of New York. It also nests in the high Appalachians as far south as Georgia. In winter the Canada warbler's range extends from Guyana to northwestern Bolivia around the northern and western side of the Andean crest.
In both summer and winter seasons the Canada warbler inhabits moist thickets. During the breeding season the bird "nests in riparian thickets, brushy ravines, forest bogs, etc. at a wide range of elevations and across a variety of forest types. In the northwestern parts of its range it frequents aspen forests; in the center of the range, it is found in forested wetlands and swamps; and in the south it occupies montane rhododendron thickets."
In the winter it prefers mid- and upper-elevation habitats. In northern Minnesota a study found that Canada warblers inhabited the shrub-forest edge, rather than marture forests or open fields with shrub. In New England the Canada warbler was found to be "disturbance specialists" moving into patches of forests recovering from wind throw or timber removal. Because of its preference for low-height foraging in deciduous forests, it may be bounded at higher elevations as suitable habitat disappears and suffer competition from the black-throated blue warbler which prefers similar habitats.
Two accidentals have been observed in Europe. The first a moribund male caught in Sandgerði, Iceland on September 29, 1973. The second was a first winter, probably female observed for five days in October 2006 in County Clare, Ireland.
The age at which the young leave the nest is not known. Once independent they spend almost all their time in the understory, on the ground or in bushes. The post-juvenile bird undergoes a partial moult involving all body feathres and wing coverlets. This may be completed before the first migration.
The oldest known specimen was a male found in Quebec in 1982 at least 8 years old, having been banded in 1975.
Canada warbler