John B. Nelson House  John B. Nelson House is a historic home close to Port Penn, New Castle County, Delaware. It was built in the early 19th century, and consists of a two-story, four-bay by three-bay core with a one-room wing. It has a two-story wing added in the mid-19th century. It is a stuccoed brick structure. It was listed on the National Register of Historic Places in 1978.