Under Oak Washington, D. C.
- Year Built: 1924
- Architect: Victor Mindeleff, Landscape architect Rose Greely
- Built By: Frank Simpson

The house at 4220 Nebraska Avenue was built in 1924, for its first owners and occupants, Mr. and Mrs. Scott E. Welker. Welker hired architect Victor Mindeleff to provide designs for the turreted Norman revival style house, which was built by Frank Simpson at a cost of $25,000, an impressive sum for the day.
The house was featured in the May 1924 issue of American Architect magazine. Many garden follies, a guard house, and an in-ground swimming pool added in the 1950s, are found in the extensive grounds that reach to the intersections of Van Ness Street with Nebraska Avenue and 42nd Street, NW.
The grounds also included the famous Dunblane oak tree. Appropriately, the new residence was named “Under Oak.”
In 1941, the estate became home to Mr. and Mrs. Wiley Buchanan, who added a large wing on the northeast side of the residence in 1951. Buchanan served as the Chief of Protocol under President Eisenhower from 1957 to 1961 and as an Ambassador to Luxembourg.
The Tenleytown Historic Resources Survey (2003) identified Under Oak as a site that merits consideration as a landmark.
Gallery photos by Sarah Hood Salomon, Garden Club of America Collection, Archives of American Gardens, Smithsonian Institution