Adult birds are 18–22 cm (7.1–8.7 in) long, span 29–33 cm (11–13 in) across the wings and weigh 35–65 g (1.2–2.3 oz), with an average of 46 g (1.6 oz). At all ages and in both sexes, the beak is dusky horn-colored, and the feet and eyes are dark. The adult male in breeding plumage has a black head, wings, back and tail, and a bright rose-red patch on its breast; the wings have two white patches and rose-red linings. Its underside and rump are white. Males in nonbreeding plumage have largely white underparts, supercilium and cheeks. The upperside feathers have brown fringes, most wing feathers white ones, giving a scaly appearance. The bases of the primary remiges are also white. The adult female has dark grey-brown upperparts – darker on wings and tail –, a white supercilium, a buff stripe along the top of the head, and black-streaked white underparts, which except in the center of the belly have a buff tinge.
The Rose-breasted Grosbeak's breeding habitat is open deciduous woods across most of Canada and the northeastern USA.
Most grosbeaks have left New England by August. However, some do not leave until Sept. or Oct. They winter primarily in Central America.