[5] Eastern hemlocks are widespread throughout much of the Great Lakes region, the Appalachian Mountains, the Northeastern United States, and Maritime Canada.

[6] Eastern hemlocks are popular as ornamental trees, thanks to their tolerance of a wide variety of soil and light conditions, as well as their characteristic drooping branches.

The eastern hemlock grows well in shade and is very long lived, with the oldest recorded specimen, found in Tionesta, Pennsylvania, being at least 554 years old.

The bottom of the leaf is glaucous with two broad and clearly visible stomatal bands, while the top is a shiny green to yellow-green in color.

It ranges from northeastern Minnesota eastward through southern Quebec and into Nova Scotia, and south in the Appalachian Mountains to northern Georgia and Alabama.

[15] It is found primarily on rocky ridges, ravines, and hillsides with relatively high levels of moisture.

[5] Eastern hemlock is generally confined to areas with highland climates, with cool and humid conditions.

Near the Atlantic coast and in the southern Appalachians where the trees often reach their greatest heights, annual rainfall often exceeds 1,520 mm (60 in).

Through Tsuga Search, hemlocks have been found with trunk volumes up to 44.8 m³ within the park,[19] making it the largest eastern evergreen conifer, eclipsing in volume both eastern white pine (Pinus strobus) and loblolly pine (Pinus taeda).

[1] A 2009 study conducted by scientists with the U.S. Forest Service Southern Research Station suggests the hemlock woolly adelgid is killing hemlock trees faster than expected in the southern Appalachians, and rapidly altering the carbon cycle of these forests.

The particular site near Lansing was chosen because its hemlocks are only lightly infested with the woolly adelgid, and enough trees are found to sustain a long-term study.

[23] From its foundation in the early Holocene (around 16,000 BP) in what is now the southeastern US, T. canadensis expanded rapidly and successfully into its potential range.

[24] However, palynological analyses show the hemlock population experienced a pronounced decline approximately 5,500 BP that lasted for about 1,000 years.

This tree, named the Seneca hemlock, grows in Cook Forest State Park, PA.

The center of maximum size development for the species is the southern Appalachians, especially the Great Smoky Mountains.

In addition, its very fine-textured foliage that droops to the ground, its pyramidal growth habit, and its ability to withstand hard pruning make it a desirable ornamental tree.

It has several drawbacks, such as a fairly low tolerance of urban stress, intolerance for very wet or very dry soils, and susceptibility to attack by the hemlock woolly adelgid, though this is treatable.

[27] In the UK, it is encountered frequently in gardens both large and small, as well as some parks, and is most common in the eastern areas of the country.

It is sometimes employed as a hedge, but is considered inferior for this usage compared to Tsuga heterophylla (western hemlock); it is not well adapted to the UK climate and as a consequence often has a poorly developed, forked and sinuous trunk there.

A partial list of popular cultivars includes:[26][30] American pioneers made tea from the tree's leafy twigs and used its branches as brooms.