Washington Township municipal offices are located at 211 Route 31 North, Washington, NJ 07882; phone: 908-689-7200.
The fist settlers in what would become Washington Township laid down roots along the Musconetcong River in the 1720s. Perhaps the first hamlet was a cluster of houses around the Mansfield-Woodhouse Presbyterian Church built ca. 1734. Colonel Mark Thomson established an iron forge at Changewater in 1741. In the mid 1700s the hamlet of Pleasant Valley developed around a mill built along the Pohatcong Creek. In the 1780s John Bowlby, Colonel William McCullough and Mark Thomson located farms along the Musconetcong River. Other families were the Laceys, Van Horns, Van Nattas, Crevelings and Van Dorens. Circa 1782 Imlaydale was first settled by John Bowlby and began to expand after the erection of a gristmill by Samuel Bowlby and Henry Dusenberry. In 1790, John Sherrerd operated Sherrerd's Mill at Pleasant Valley, supplying flour to Washington's army encamped in Morristown. In 1820 Jesse Vanetta and Michael B. Bowers established the Village of Bowerstown by building an iron foundry in the area to the north of Washington Borough, near the coming Morris Canal and Pohatcong Creek.