1693 - George Mason II erected a foundation to serve as a fort to protect settlers against the Dogue Indians. Located in what is now Fairfax County, it is probable that the first part of the original Hollin Hall was built on the fort foundation in the early 1720s.
1721 - George Mason III married Ann Thomson, and took up residence on this site.
1735 - George Mason IV inherited 2000 acres for a plantation contiguous to George Washington’s Mount Vernon, where he built Gunston Hall.1791 - George Mason IV spent years building a new, larger home for his son, Thomson, about 200 feet from the original house. It was named Hollin Hall after a family home in Yorkshire, England. Thomson and his wife Sarah McCarty Chichester lived in the house until his death in 1820.
1827 - The main building burned, resulting in the "spinning house" being used again as the main residence. This building is still in existence and is known as "Little Hollin Hall", located on six acres of land on what is now Sherwood Hall Lane.
1852 - Hollin Hall and 500 acres of land was purchased by Edward Curtis Gibbs, a Quaker sea captain and farmer who hirerd both black and white farmers to demonstrate that plantations could be made profitable without slave labor.
1860-65 - During the Civil War, , being considered a no-man’s land, Mason Hill was alternatively occupied by both Northern and Southern troops. After the war, it was divided among several owners.
1881 - A Thomson family member bought 300 acres from Mr. Gibbs, where the Thomson Dairy was established.
1914 - Thomson sold his estate, including six hundred acres to Mr. and Mrs. Harley Peyton Wilson.
1919 - A new mansion was completed, and the following year work was completed on other buildings and a formal garden.
1929 - A guest house and swimming pool were added, and over the years provided a retreat for Mrs. Woodrow Wilson, Herbert Hoover, and other dignitaries. Eventually, the guest house became the chapel for Mt. Vernon Unitarian Church.
1934 - Mr. Wilson died, and the estate was put up for sale.
1941 - Mr. Merle Thorpe purchased eighty-nine acres of the property that contained the mansion and turned it into a chicken and turkey farm.
1958 - The Mount Vernon Unitarian Church purchased 10.34 acres (with buildings) for its religious programs.
1978 - The new housing development on Mason Hill left intact ten acres of buildings and grounds for the Mt. Vernon Unitarian Church; and it provided a through street (Mason Hill Drive) from Fort Hunt Road to Range Road, giving direct access to the Hollin Hills and Hollin Meadows residential areas.
1984 - The final three lots were sold for new houses on Mason Hill Drive and Windmill Lane. The Unitarian Church began a major construction program that involved the sale of the old chapel and demolition of several smaller buildings.
1993 - Hollin Hall was placed on the Fairfax County Inventory of Historic Sites.
Currently - The Mason Hill neighborhood includes 115 households, including the Unitarian Church.