The publicly owned, 295-acre Original Mason-Dixon Historical Park was established in the 1970s to commemorate the great achievement of Charles Mason and Jeremiah Dixon, the English astronomers who surveyed the Mason and Dixon Line. Brown's Hill is a National Historic Landmark and the Mason and Dixon Line is a National Civil Engineering Landmark. This location has been so honored because it was on Brown's Hill that Mason and Dixon were obliged to end their survey, 23 miles short of their goal.

In 1763 the English astronomers Charles Mason and Jeremiah Dixon were hired to settle an 82-year boundary dispute between Penns and Calverts, who had received royal grants in America. They kept a daily detailed journal that was lost for a century; reprints are available at this park. They describe the process of obtaining permission from the Indians to draw the line westward, and the travails of a 4-year, 240-mile mission, cutting a 24-foot-wide swath over mountains and across rivers through the wilderness.

Although relations with the native Americans they met and worked with were friendly, there came a point, on October 9, 1767, a warpath, at which safe passage ended. They did continue a short distance, crossing Dunkard Creek three times. For 10 days they made astronomical observations and established their final survey point on top of a steep ridge. Then they returned eastward, unable to complete the last 23 miles of their survey. It was completed 14 years later by other surveyors.

The Line divides the park with half being in Pennsylvania and half in West Virginia. Volunteers from Greene County and Monongalia County have worked to create a recreational resource for the citizens. The two counties appoint members to the park's board of directors.

Park facilities are available to rent year-round, including pavilions with modern restrooms, a ballfield, and a large red barn with cooking and dining facilities. Visitors have enjoyed ramp dinners in the spring and buckwheat/sausage dinners in the fall for many years at the park. The 295 acres of meadow and woodland is always available for hiking. Dunkard Creek is a popular fishing stream and the park is headquarters of the Dunkard Creek Watershed Assn.