In June 1776, American Patriot officers Henry Knox, Nathanael Greene, William Heath, and Israel Putnam examined the terrain on which Fort Washington would be located; they agreed that if the fort was properly fortified, it would be practically impossible to take. Later in June, the Commander-in-Chief of the Continental Army, George Washington, inspected the location and determined that the area was the key to defense of the lower Hudson. Shortly after Washington's survey, troops from Pennsylvania began construction on the fort under the supervision of Rufus Putnam.