Delaware — Shell House, $13.9 Million
Delaware’s most expensive residence combines ocean and lake living. The 7,800-square-foot home is located on Penn Street, and it borders the popular Reheboth Beach on one side and Silver Lake on the other. It’s a rare offering for this alone, but it’s also a home with ties to state history. The cottage was originally built in 1920 by the Du Ponts, a family that was once among America’s wealthiest and that held a great deal of influence in Delaware. Its current owner purchased the seven-bedroom about 20 years ago, the first owner that wasn’t a Du Pont, and restored and expanded the property to maximize lake and ocean views.