Since the early 1700s, Franklin County PA was America’s frontier, and one of the earliest families to settle along this part of the frontier was the Johnston family. Dr. Robert Johnston was the original owner of the tract of land on which Martins mill bridge is located.

Dr Johnston served as a surgeon in the Continental Army during the Revolutionary War, where he befriended George Washington. In fact, when Washington was on his way to put down the Whiskey Rebellion, Dr Johnston entertain him along with Alexander Hamilton at his home in Greencastle.

Years later, a subsequent owner of the land, Samuel Martin, built a sawmill and grist mill on the land along the Conococheague Creek. Martins mill bridge was constructed to replace a creek fording, which became impossible to cross when the creek’s water was high. Bridges in Franklin County PA are the responsibility of the county, so the Franklin County Commissioners¬† contracted Jacob Shirk to construct the bridge in 1848. The wood used to construct the bridge was sawed at the Martins Mill, hence the name Martin’s Mill Bridge.

The trusses of the bridge use the design of Ithiel Town, a Connecticut architect who popularized the use of a truss consisting of a lattice of heavy timber with each crisscrossing intersection pinned with a minimum of two, 2-inch diameter wooden pins. Such construction could bear a span of up to 200 feet without additional support. The Martin’s Mill Bridge is 205 feet. Bridge constructor Jacob Shirk wanted to assure sturdy construction and added a stone support halfway across the bridge.

Martin’s Mill Bridge was nearly swept away by the Conococheague Creek in June 1972 when Hurricane Agnes created powerful floodwaters. Local engineering firm Nassaux Hemsley and hydraulic crane construction company Grove Manufacturing work together on the reconstruction. Adding the labor of local volunteers, the US Army 377th Engineer Battalion, and the US Army 357 transportation company made the reconstruction of Martin’s Mill bridge possible. It was rededicated in June 1973.

The bridge was recently rededicated in mid-October after a fourth renovation was completed. The process of planning and funding the fourth renovation began in 2007. Total cost to renovate Martin’s Mill Bridge was $1.1 of which $700,000 was allocated from the Federal Highway Administration Covered Bridge Preservation Program, according to a Antrim Township documents. ¬†The project was directed by P. Joseph Lehman Inc. Consulting Engineers of Hollidaysburg, PA. Work included installation of a steel support beam, new siding and portals, replacement of the roof, replacement of decayed wooden structural pieces, and staining.

Martin’s Mill Bridge is one of two covered bridges in Franklin County with the another– Witherspoon Bridge–located near Mercersburg PA. Martins Mill Bridge is the second largest covered bridge in the state of Pennsylvania and the largest lattice truss bridge. It is included on the National Register of Historic Places. The bridge is located at Martin’s Mill Bridge Park, which includes picnic tables, grills a pavilion, restroom facilities and access to the Conococheague Creek for kayaking. It is a dawn to dusk facility.