In 1775 and 1776, Wallace bought 12 acres (4.9 ha) more land, and in 1776 built an eight-room Georgian mansion next to the farmhouse.

[5][6] The Continental Army camped in the Watchung Mountains at Middlebrook, 3 miles (4.8 km) from Hope Farm during the winter of 1778–79.

The Wallace House became George Washington's headquarters, though he only stayed there for 11 days before leaving to attend the Continental Congress in Philadelphia for 6 weeks.

Guests at the parties included Benedict Arnold, Nathanael Greene, Alexander Hamilton, Henry Knox, and Baron Steuben.

John Wallace, his wife, and his mother-in-law all died in 1783–84, and his youngest son William inherited Hope Farm.