 Isaac Anderson was born at "Anderson Place," in then Charlestown Township, Pennsylvania now Schuylkill Township, Chester County, Pennsylvania, near Valley Forge, Pennsylvania, the son of Patrick Anderson and grandson of early settler James Anderson.As a youth he was the carrier of dispatches between the headquarters of the Revolutionary Army under General George Washington at Valley Forge and the Congress, then in session at York, Pennsylvania.He served three terms of service in the American Revolutionary War before reaching the age of eighteen, at which time he became an ensign in the Fifth Battalion of Chester County Militia.