Parr’s Spring holds a unique place in Maryland’s geography and history, most notably as the only point in the state where four counties converge– Carroll, Frederick, Howard, and Montgomery.
This historically significant location also marks the headwaters of the South Branch of the Patapsco River, which eventually flows into Baltimore Harbor, underscoring its natural importance beyond its role as a boundary marker. The spring, named after 18th-century landowner John Parr, has been recognized on maps and in land records since at least 1726, consistently serving as a crucial landmark for county delineations despite shifts in county lines over centuries.
Today, Parr’s Spring is submerged within a pond on a property known as “Four County Farm,” where a modern concrete marker and submerged boulders are believed to signify this unique geographical intersection. It’s on private property, so a visit without permission is not advised.
Additional photos can be seen here. Sources:
Maryland Department of Natural Resources. “Patapsco River State Park.” Maryland DNR
Baltimore Sun. “Parr’s Spring marks where four counties meet.” Baltimore Sun, October 14, 2011
Carroll County Government. “History of Carroll County.” Carroll County Maryland,