Island beaches, sparkling waters, bayous, historic forts and recreational opportunities are plentiful in Gulf Islands National Seashore, the nation’s largest. Open year-round, the Seashore is in Mississippi and Florida. Gentle breezes, tides and hurricanes constantly reshape this dynamic landscape. More than 80 percent of the park is submerged lands teeming with marine life. Marshes collect fresh rainwater and support diverse communities of plants and animals. Live oak forests are home to resident and migrating bird populations. Leashed pets are allowed in developed areas, such as parking lots, and along gravel and paved roads. Pets are not allowed in the buildings, on the beaches, or in the picnic pavilions. Leashes must be no longer than six feet.