Fort Jefferson is a historic military fortress located in the Dry Tortugas National Park in Florida, USA. Here are key features and information about Fort Jefferson and its location:

1. Location: Fort Jefferson is situated on Garden Key, one of the islands in the Dry Tortugas, which is a remote and pristine group of islands located about 70 miles (113 kilometers) west of Key West, Florida.
2. Construction: Construction of Fort Jefferson began in 1846 and continued for several decades. The fort was designed to serve as a strategic military outpost to protect the Gulf of Mexico and the Florida Straits.
3. Purpose: The primary purpose of Fort Jefferson was to provide protection for the United States during a time of increased maritime activity, especially related to shipping in the Gulf of Mexico and the strategic location of the Florida Keys.
4. Architecture: Fort Jefferson is a massive coastal fortress with a hexagonal shape. It features a unique design with large walls and a courtyard, and it was initially intended to mount over 400 cannons.
5. Materials: The fort was constructed using more than 16 million bricks, making it one of the largest masonry structures in the Americas. Due to its remote location, the materials for construction had to be transported over great distances.
6. Civil War Use: During the Civil War, Fort Jefferson served as a military prison for Union deserters. Notable prisoners, including Dr. Samuel Mudd (who treated John Wilkes Booth), were held at the fort.
7. Abandonment: Despite being a formidable fortress, Fort Jefferson was never fully completed or armed. Advances in weaponry and changing military strategies made coastal forts less strategically valuable, leading to the fort’s abandonment.
8. National Park Status: In 1992, Fort Jefferson and the surrounding Dry Tortugas were designated as Dry Tortugas National Park. The park encompasses marine life, coral reefs, and historic structures, including the fort.
9. Tourism and Access: Today, Fort Jefferson is a popular tourist destination, attracting visitors who arrive by ferry, private boat, or seaplane from Key West. The site offers guided tours, snorkeling opportunities, and a chance to explore the historic fort and its surroundings.
10. Wildlife: In addition to its historical significance, Dry Tortugas National Park is known for its diverse marine life, coral reefs, and bird populations. The area is a haven for snorkelers, scuba divers, and nature enthusiasts.

Visitors to Fort Jefferson and Dry Tortugas National Park can experience a combination of history, natural beauty, and outdoor recreation in a unique and remote setting. It remains a fascinating destination that showcases the historical and ecological richness of the Florida Keys.