The Seven Days Battles were a series of seven battles over seven days from June 25 to July 1, 1862, near Richmond, Virginia, during the American Civil War. Confederate General Robert E. Lee drove the invading Union Army of the Potomac, commanded by Maj. Gen. George B. McClellan, away from Richmond and into a retreat down the Virginia Peninsula. The series of battles is sometimes known erroneously as the Seven Days Campaign, but it was actually the culmination of the Peninsula Campaign, not a separate campaign in its own right.

The Battle of Beaver Dam Creek, also known as the Battle of Mechanicsville or Ellerson's Mill, took place on June 26, 1862, in Hanover County, Virginia. It was the first major engagement of the Seven Days Battles during the Peninsula Campaign of the American Civil War. It was the start of Confederate General Robert E. Lee's counter-offensive against the Union Army of the Potomac, under Maj. Gen. George B. McClellan, which threatened the Confederate capital of Richmond. Lee attempted to turn the Union right flank, north of the Chickahominy River, with troops under Maj. Gen. Thomas J. "Stonewall" Jackson, but Jackson failed to arrive on time. Instead, Maj. Gen. A.P. Hill threw his division, reinforced by one of Maj. Gen. D.H. Hill's brigades, into a series of futile assaults against Brig. Gen. Fitz John Porter's V Corps, which occupied defensive works behind Beaver Dam Creek. Confederate attacks were driven back with heavy casualties. Porter withdrew his corps safely to Gaines Mill, with the exception of Company F of the 8th Pennsylvania Reserve Regiment who did not receive the orders to retreat.