The Second Battle of Dranesville, also known as the Ambush at Anker's Shop, was a small cavalry skirmish that took place between Confederate forces under Colonel John Mosby and Union forces under Captain James Sewall Reed east of Dranesville, Virginia in Loudoun County near present-day Sterling on February 22, 1864, as part of Mosby's operations in Northern Virginia in the American Civil War.

On February 20 a detachment of Cole's Maryland Cavalry, 200 strong, left Harpers Ferry for Upperville, where they surprised and captured 11 of Mosby's Rangers.

They then set out south for Piedmont Station (present day Deleplane), shortly thereafter they came upon another partisan, Bill McCobb, who rushed to his horse, but was thrown from it and killed when it jumped a fence.

Mosby, who was at the Heartland farm on the road to Piedmont Station with four of his officers, was alerted off the oncoming Federals by a scout as they ate breakfast.

A running fight ensued for 3 miles (4.8 km) until Cole reached the ground of Blackleys Grove School and halted.

As he withdrew he placed skirmishers behind the numerous stone walls he crossed, impeding the Ranger's pursuit.

As the Federals bivouacked, Mosby rejoined his main body, who he had since directed to Guilford Station (present day Sterling) on the Alexandria, Loudoun and Hampshire Railroad.

Moments later, Ranger Baron Robert von Massow captured Reed, but he too failed to take his side arm and was also shot in the back.