Union generals Hooker and Sickles were both in Maryland. Hooker’s subordinate, Daniel E. Sickles, commanded New York’s “Excelsior” Brigade. Balloon reconnaissance operations in December of 1861 monitored Confederates along the Potomac from Quantico Creek south to Chopawamsic Creek in Stafford.
On April 2, 1862, General Dan Sickles and his Excelsior Brigade raided across the Potomac to Stafford, engaging Southern troops at Aquia Church and Stafford Court House, before withdrawing to Maryland.
Two weeks later, over 40,000 Federal troops advanced into Stafford to begin the First Federal Occupation.