Thoroughfare Gap Battlefield in Prince William County, Virginia

Hike nature trails and visit the ruins of a Colonial-Era mill at this historic battlefield in the Bull Run Mountains.

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The Battle of Thoroughfare Gap (Chapman’s Mill) was fought on August 28, 1862 between Union forces commanded by Brig. Gen. James B. Ricketts and Col. Percy Wyndham and Confederate forces commanded by Maj. Gen. James Longstreet in Fauquier and Prince William Counties, Virginia during the American Civil War. The battle was a Confederate victory, allowing two wings of the Confederate army to unite and win the Second Battle of Bull Run over the following three days. It resulted in 100 total casualties.

In late August 1862, Confederate Gen. Robert E. Lee’s Army of Northern Virginia squared off against Union Maj. Gen. John Pope’s Army of Virginia 40 miles from Washington, DC. Lee outmaneuvered Pope, sending Maj. Gen. Thomas J. “Stonewall” Jackson’s wing around Pope’s flank to destroy his supply depot at Manassas Junction. Confederate Maj. Gen. James Longstreet followed with the rest of the army. To reach Jackson, Longstreet had to pass through Thoroughfare Gap in the Bull Run Mountains.

To delay Longstreet and his 28,000-man force, Pope sent one brigade commanded by Brig. Gen. James B. Ricketts and a regiment of cavalry commanded by Col. Percy Wyndham, a British adventurer who volunteered to fight with the Union Army. Their force totaled approximately 5,000 men. On August 28, Wyndham was guarding the pass when Longstreet’s men began to march through. The cavalry retreated and sent for help, but Ricketts’ small brigade was severely outnumbered. By the time Ricketts arrived with reinforcements, Longstreet’s lead units held the high ground and easily fended off several Union attacks.

When the smoke cleared, 75 Union and 25 Confederate soldiers lay dead or wounded. With such a numerical advantage, a Confederate victory was probably inevitable, yet Union forces bungled an opportunity to significantly delay Longstreet and half the Confederate army. This failure allowed Longstreet to reunite with Jackson on August 29th at the Second Battle of Bull Run, where they crushed Union Maj. Gen. John Pope’s Army of Virginia.

Fought between Northern and Southern states from 1861 to 1865, the American Civil War erupted over questions of slavery, the legality of secession, and the primacy of the Federal government. It ended with Northern victory and restoration of the Union. Nearly 850,000 people died in the conflict, the bloodiest war in U.S. history. Most of the war’s battles were fought in the South, devastating its economy and leaving generational scars.

Today, Interstate-66 and John Marshall Highway run through Thoroughfare Gap. Thousands of motorists pass by every day unaware of the historic events that took place there. Thoroughfare Gap Battlefield was added to the National Register of Historic Places in 1999. The American Battlefield Trust has preserved 109 acres of the battlefield, and other portions are in the Bull Run Natural Area Preserve (only open to hikers on weekends). The Beverley Mill ruins have been closed for renovations since 2019.

Built in 1759, Beverley Mill (aka Chapman Mill), was a stone grist mill in operation through World War 2. Jonathan and Nathaniel Chapman constructed the mill and owned it during the Civil War, when their property suffered from the ravages of war. John Chapman had a nervous breakdown and was committed to an insane asylum in 1864, where he died. Vandals burnt the historic mill in 1998. It was added to the National Register of Historic Places in 1972.

Civil War Trail signs for Thoroughfare Gap and the Campaign of Second Manassas are located along John Marshall Highway near GPS coordinates 38.823494, -77.7109. Beverley Mill AKA Chapman’s Mill ruins are located at 17504 Beverley Mill Drive in Broad Run, Virginia. There is a small gravel pull off for parking.