Marden House, also known as Fontinalis, is a historic residence in McLean, Virginia, designed by Frank Lloyd Wright for National Geographic writer, photographer, and explorer Luis Marden. Overlooking the Potomac River near Chain Bridge Road, it grew from a site Marden and his wife noticed while fishing in 1944. Marden had begun corresponding with Wright in 1940 and persistently sought a design for the property until plans arrived in 1952. Completed in 1959 at a cost of $76,000, the house is significant for its Wright authorship, its carefully chosen riverside setting, and the long personal effort that brought this late Wright design to the Washington area.