The Moravian Museum of Bethlehem, also known as the 1741 Gemeinhaus and the Lewis David de Schweinitz Residence, is a historic house museum at 66 West Church Street in Bethlehem, Pennsylvania. Built in 1741 to house the early Moravian community as well as the community's place of worship, the Saal, it is the oldest surviving building in Bethlehem, the largest surviving log house in continuous use in the U.S. and also significant for its association with the botanist and mycologist Lewis David de Schweinitz (1780–1834). It was declared a National Historic Landmark in 1975. The building is part of the Historic Moravian Bethlehem District which was designated as a National Historic Landmark District in 2012 and later named to the U.S. Tentative List in 2016 for nomination to the World Heritage List.