The Upper Keys are a popular, year-round refuge for South Floridians who take advantage of the islands' proximity to the mainland. This is the fishing and diving capital of America, and the swarms of outfitters and billboards never let you forget it.

Key Largo, once called Rock Harbor but renamed to capitalize on the success of the 1948 Humphrey Bogart film (which wasn't actually filmed there), is the largest Key and is more developed than its neighbors to the south. Dozens of chain hotels, restaurants, and tourist information centers service the many water enthusiasts who come to explore the nation's first underwater state park, John Pennekamp Coral Reef State Park, and its adjacent marine sanctuary. Islamorada, the unofficial capital of the Upper Keys, offers the area's best atmosphere, food, fishing, entertainment, and lodging. It's an unofficial "party capital" for mainlanders seeking a quick tropical excursion. Here (Islamorada is actually composed of four islands), nature lovers can enjoy walking trails, historic explorations, and big-purse fishing tournaments. For a more tranquil, quieter, less party-hearty Keys experience, all other Keys besides Key West and Islamorada are better choices. Marathon, smack in the middle of the Florida Keys, is one of the most populated Keys and is known as the heart of the Keys. It is part fishing village, part tourist center, and part nature preserve. This area's highly developed infrastructure includes resort hotels, a commercial airport, and a highway that expands to four lanes.