The Rufus Putnam House, also known as Campus Martius or Campus Martius Museum State Memorial, is a historic building in Marietta, Ohio. It was built as part of the Campus Martius fortification by General Rufus Putnam, during the early settlement of Ohio by the Ohio Company of Associates. The building is listed in the National Register of Historic Places individually, and it is also a contributing property of the Marietta Historic District. The building is the only surviving part of the Campus Martius fortification and has been enclosed inside the Campus Martius Museum building.