Purple Swamphens are large members of the rail family (Rallidae). Males are generally larger than females, with males averaging around 1,050 grams and females about 850 grams. These chicken-sized birds feature dark, glossy indigo or purple feathers, red bills, and prominent frontal shields. While their plumage color can vary by region, they typically have dark green, brown, or black backs and wings with a greenish sheen, and their breasts and heads range from pale blue to purple-blue. Their tails are short, and the undersides of their tails display bright white feathers. Their legs are long, scaly, and orange-red.