A Monongahela village was settled just outside the borders of the future Mason-Dixon Historical Park between 900 and 1200 AD. In 1632, King Charles I issued the Maryland land grant for the area between the 40th parallel and the Potomac River, extending from the Delaware River west to the source of the Potomac at the Fairfax Stone, and in 1681 Charles II issued the later land grant that became Pennsylvania. Inaccurate descriptions and poor survey work led to 80 years of boundary disputes. In 1763, the Royal Society of Astronomers at Greenwich commissioned Charles Mason and Jeremiah Dixon to begin the survey. The work stopped on June 9, 1766, until safe passage could be negotiated with the Six Nations council, then resumed in 1767 with Indigenous participants from the Six Nations, including 11 Mohawks and 3 Onondagas, as well as others from the Delaware Tribe and Seneca Nation. On October 9, Mason wrote that the party crossed a War Path and crossed Dunkard Creek three times, and the chief informed them that the War Path marked the extent of his commission and that he would go no farther westward. From October 10-19, the surveyors ended their line on what is now Brown's Hill, 23 miles short of their goal, where Mason recorded that they set up a post and heaped earth and stone around it. Mason and Dixon returned to England in 1768. In 1784, David Rittenhouse and Andrew Ellicott completed the survey to the corner of Pennsylvania and north, giving West Virginia a panhandle. In 1883, C.H. Sinclair placed a stone monument in the center of the old mound. In 1969, after Consolidated Gas purchased the property from Charles and Delores LaPoe, Dr. Eldon Tucker of nearby Cassville learned that Mason and Dixon had ended their famous boundary line on Brown's Hill and joined other local history supporters in promoting a park there. Consolidated Gas gave the property to Monongalia County on March 18, 1977. In 1983, volunteers in Mason-Dixon Historical Park, Inc., received permission from the Monongalia County Commission to begin park development, funded mostly by Monongalia County, along with rentals, events, and some support from Greene County. In 2001, the Monongalia County Commission began managing Mason-Dixon Historical Park, Chestnut Ridge Park, and Camp Muffly. In October 2017, the park celebrated the 250th anniversary of the end of Mason and Dixon's survey. Today the park offers more than 5 miles of trails, access to Dunkard Creek, seasonal recreation, and community events.