Jonah crabs are found along the Atlantic coast of North America. Their range begins near Nova Scotia and extends southward, at least as far as South Carolina and possibly Bermuda. Jonah crabs are found from the intertidal zone to about 640 metres, although they usually found in depths of 50-300 metres and at temperatures of 8-14° Celsius. They live in a variety of ocean beds, including rocks, clay, sand and mud.

Jonah crabs have an oval-shaped carapace with a rough texture. They have two large, powerful pincers and eight short, thick legs. Their colour is usually red on top and yellowish on their underside, sometimes with a mottling of yellow and red on their legs. Jonah crabs can grow to a maximum carapace width of about 180 mm, with males growing larger than females.