Gulph Mills Monument The inscription on the stone reads as follows: GULPH MILLS, The Main Continental Army Commanded By GEORGE WASHINGTON Encamped in this Immediate Vicinity From December 13, to December 19, 1777 Before Going into Winter Quarters At Valley Forge Erected By THE PENNSYLVANIA SOCIETY OF SONS OF THE REVOLUTION 1892 This monument is located in Gulph Mills Township Park, on the south side of Longview Road, Upper Merion Township, Montgomery County. It was a gift to the Society by Joseph E. Gillingham of Philadelphia. In 1986 residential development of the land on which this great natural boulder had originally been placed required it relocation across Longview Road to the present site.