In 1738, the East Conococheague Congregation established the Presbyterian’s red meeting house at Moss Spring; the site selected due to this water source. By 1741 Antrim Township was established, including all the land in the area.

The land at the center of the township, would become Greencastle at the intersection of the much traveled trails, Baltimore and Carlisle pikes. Here is where Allison’s Tavern hosted cattle and sheep herders and businessmen who would make their way south from Harrisburg and Carlisle to the Potomac to sell their wares or from Baltimore north to Pittsburgh bringing goods and then purchasing other items wanted or needed before the trip home.

William Allison, who operated the tavern, gave his son John 300 acres of land. With the help of school teacher James Crawford, the land was surveyed and developed into 246 building lots. The area began to grow once it was founded by John Allison in 1782. The name Greencastle was a reminder of the town in northern Ireland from where many of the new residents’ ancestors had emigrated.

The Scot-Irish Presbyterians were followed by the Germans, Lutherans and Reformed. All the settlers and their families brought their unique customs and names with them, adding to the culture and eventually, the history of the region. By 1794 there were reportedly 60 houses in the village and George Washington passed through Greencastle in October of that year, stopping at McCullough’s Tavern on the southwest section of the Square.