The family Rallidae includes 13 species found in North America.

Rails occur worldwide in temperate and tropical climates and live mostly in swamps, marshes and wet grasslands. Some occur in dry habitats. They are small to medium-sized. The body can be laterally compressed ("skinny as a rail") in typical rails. The bill varies in length and shape from long and curved to short and conical. Wings are short and rounded. Many island forms are flightless. Adult plumages tend to be alike in the sexes, but females are smaller. 

The food of most species is entirely or mainly animal, including insects, worms, mollusks and other small invertebrates. Larger rails may take frogs, small fish and bird's eggs. Coots feed on aquatic plants by diving or on the surface.

Rails build their nests of plant materials on swampy ground in dense vegetation, among bent reeds over shallow water or on tussocks. Some species construct a roofed nest. Coots may nest in less dense vegetation or in open areas at the edge of reedbeds or on floating platforms. Clutches range from 1-14 eggs. Largest clutches may result from more than one female laying in a nest. Egg color varies from white to buff with spots and blotches of reddish, gray, brown or black. Incubation is usually by both sexes, in some species only by the female, for 2.5-4 weeks. Nestling downs are black or dark brown in rails; reddish in at least some coots. The young leave the nest soon after hatching and are cared for by both parents until they are independent.

The greatest incidence of flightlessness occurs in rails and most flightless rails have evolved on islands. Many have become extinct due to human influences, including the introduction of predators, but at least 15 subspecies and species of flightless rails are still alive. Flightlessness evolves to conserve energy where resources are low and mammalian predators are absent.