Biscayne National Park's 172,000 acres play host to over 500,000 visitors per year. Though that number is 3 to 4 times the number of visitors per acre of any other national park in South Florida, you'll rarely see crowds here. Unlike many parks where visitors are generally confined to roads, trails and developed areas, Biscayne's visitation is much more dispersed. In some ways, that means that overall impacts to the resource by such large numbers of people are spread out and less noticeable. In other ways, it means that just about every part of the park is accessible to some sort of boat, so true wilderness can't really be found in the nation's largest marine park.
Learn more about the park's acreage and visitation (including monthly and yearly breakdowns) on the Public Use Statistics Office website.