The Johannes Jansen House, also known as Johannes Jansen House and Dutch Barn, is located along Decker Road at the foot of the Shawangunk Ridge in the western section of the Town of Shawangunk, in Ulster County, New York, United States. It was started by Jansen, who had settled the area along with his brother Thomas, whose own house is a mile (1.6 km) to the southeast, in 1750. His son finished it in the newer Federal style 53 years later. The property also boasts a Dutch barn.