The Bay-breasted Warbler nests in boreal forests, usually with a spruce component, from southeastern Yukon across central Canada to the northern Great Lakes, New England, and Atlantic Canada. It winters from Costa Rica and Panama to Colombia and Venezuela, migrating for the most part across the Gulf of Mexico.
All plumages show greenish upperparts, streaked back, two prominent white wing bars, and unstreaked underparts. Breeding-plumaged adults are easy to identify, with bay crown, upper breast, and flanks; dark face; and buffy sides to the neck. Immatures and fall birds are among the most confusing of all warblers, even with good views.