The Eastern Cottontail (Sylvilagus floridanus) is a New World cottontail rabbit, a member of the family Leporidae. It is one of the most common rabbit species in North America.

The Eastern Cottontail is chunky red-brown or gray-brown in appearance with large hind feet, long ears and a short fluffy white tail. Its underside fur is white. There is a rusty patch on the tail.

Its appearance differs from that of a hare in that it has a brownish-gray coloring around the head and neck. The body is lighter color with a white underside on the tail. It has large brown eyes and large ears to see and listen for danger. In winter the cottontail's pelage is more gray than brown. The kittens develop the same coloring after a few weeks, but they also have a white blaze that goes down their forehead; this marking eventually disappears. The average adult weighs about 2-4 pounds; however the female tends to be heavier.

The Eastern Cottontail can be found in meadows and shrubby areas in the eastern and southwestern United States, southern Canada, eastern Mexico, Central America and northernmost South America. It is abundant in Midwest North America, and has been found in New Mexico and Arizona. Its range expanded north as forests were cleared by settlers. Originally, it was not found in New England, but it has been introduced there and now competes for habitat there with the native New England Cottontail.

The Eastern Cottontail eats green vegetation such as grasses and clover in summer and bark, buds and twigs in winter. Its diet includes grasses, fruits, and vegetables in the spring and summer, and twigs, bark, dogwoods and maple trees in the winter. This animal is active at night; it does not hibernate in winter. Predators include hawks, owls, coyotes, wolves, mustelids and lynx. People also hunt it for food in many parts of its range; its fur is also used for clothing.

On farms and in gardens, the Eastern Cottontail is usually considered a pest and is often trapped or shot to protect plants.

Mating occurs from February to September. Males will mate with more than one female. Female rabbits have 2 to 4 large litters of up to 9 young, called kits or kittens, in a year. The female builds a nest in the ground lined with grass and fur. After the female has given birth to her offspring, she can mate again immediately thereafter. The kittens are weaned after 3 weeks and leave the nest after seven weeks. The kittens then reach mating age after three months.

Hunting and predation prevent the rabbit population from growing out of control. About 20-25% of the young rabbits live in a year and 85% of adults or young are killed every year by predators (including humans).

The Eastern Cottontail is a very territorial animal. It is nocturnal and is also active during early dawn and late dusk. When running, it can jump from 10-15 feet, which can aid in avoiding predators. When chased, it runs in a zigzag pattern so the animal chasing it will lose its scent and so the rabbit is harder to follow. It can run up to 15mph. The cottontail prefers an area where it can hide quickly but be out in the open. Forests, swamps, thickets, bushes or open areas where it can dig a burrow are optimal habitation sites for this species.