Despite many changes, Harriton is important as one of the seeds of its community. Built by Rowland Ellis, one of the early Welsh immigrants, and named “Bryn Mawr” (Welsh for “high” or “big hill”), its rubble stone walls have witnessed most of Lower Merion's history. The house was renamed “Harriton” when it was acquired by Richard Harrison in 1719; it was later owned by Charles Thomson, secretary of the Continental Congress and longtime correspondent with Thomas Jefferson.
Research suggests that the house was originally an unusual medieval T-plan with a central wing. In the twentieth century, the house underwent a series of changes that shifted its appearance and interior space toward the regional Georgian ideal, much of which was undertaken by its owner Ralph Colton, an architect and nephew of the important Colonial Revival architect Horace Wells Sellers. His work was largely undone in a 1970s restoration but many questions remain. The main facade has been restored with a pent eave once again across the top of the first floor and a balcony above the entrance, rather like