Measurements:[2] Adults have streaked rusty, buff and black upperparts with an unstreaked gray breast, light belly and a white throat.

A small number of morphologically distinct birds inhabit tidal marshes from northern Virginia to the Hudson River Estuary.

The bulky nest is attached to marsh vegetation, often just above the ground or surface of the water with leaves or grass arching over the top.

[3] Females give a series of chips as they leave the nest, probably to ward off attacks by their mate or neighboring males.

While swamp sparrows can be found year-round in small numbers on the southern edge of their breeding range, individuals are probably all migratory, primarily migrating to the southeastern United States.