Square Feet: 50,000
This mega mansion located on Hutchinson Island in Jensen Beach is the largest home ever built in Martin County. The home was built for Robert Eustace who is the founder of software supplier Applied Systems, headquartered in University Park, Ill. The main residence contains 20,000+ square feet of living space and 50,000+ including garages and decks. The mansion reportedly cost $8 million to build and includes 42 gothic columns, 11 domes, 11 rotundas, 4 bedrooms, 6 bathrooms, and 8 entertainment rooms. The property also includes an 11,500 (included in the 50,000 total square footage) guest house complete with 3 to 4 bedrooms and 5 1/2 baths.