Our Documentary Heritage showcases holdings drawn from the vast collections of the Pennsylvania State Archives.

This section of an 1875 map contained in the Map Collection (Manuscript Group 11, Second Geological Survey, Map # 180–40) at the Pennsylvania State Archives depicts the site of the Safe Harbor Iron Works in Conestoga Township, Lancaster County, where the three-inch Ordnance Rifle designed by John Griffen (but commonly called a Griffin Gun) was first manufactured and tested in 1855. This wrought iron cannon was a major advance over the prevailing cast iron artillery that too often burst during use. The Griffin Gun employed by Union forces had a greater effective range and accuracy than the Parrot cast iron gun relied on by Confederate forces. Only one Griffin Gun is known to have burst in service during the entire course of the war despite being one-hundred pounds lighter than the standard Parrot Gun.

Born in Westchester County, New York, in 1812, John Griffen was a natural innovator who erected a new ironworks for the firm of Moore and Hoven at Norristown, where he invented a system for reclaiming heat from the iron puddling furnaces to create steam for the plant. By 1847 Griffen was commissioned by Reeves, Archer and Company to build another new blast furnace, foundry, and rolling mill on the Conestoga Creek at Safe Harbor, Lancaster County, where he served as superintendent. In addition to turning out rails at Safe Harbor for the Pennsylvania Railroad Company he designed a new type of governor to control the speed of engines in the rolling mill and employed steam power to transport the rails for sawing. In 1854 he designed his new gun using wrought iron rods welded together to form a mandrel and then winding a long iron bar around this in a spiral fashion by revolving a lathe. After three successive layers of iron bar were applied in a crosswise fashion to the mandrel, a thin layer of staves was applied to the exterior and a plug driven to form a breach.

According to a period account, “welding heat was then applied and the mass rolled out to a length of seven feet. Trunnions were welded on and the gun was bored and rifled from the solid.” The weapon patented in December 1855.

In 1856 Griffen moved his operations to Phoenixville, Chester County, where he operated the Phoenix Iron Works that went on to manufacture a large number of modified Griffin Guns for the Union army beginning in 1861. The Safe Harbor Iron Works also manufactured Dahlgren Guns for the United States Navy during the Civil War until it was damaged by a flood in 1865. The rebuilt Safe Harbor Iron Works was abandoned in 1894.


Willis L. Shirk Jr. is an archivist with the Pennsylvania State Archives.