Soon after the start of the Civil War, Reynolds was offered the position as aide-de-camp to Lt. Gen. Winfield Scott, but declined. He was appointed lieutenant colonel of the 14th U.S. Infantry, but before he could engage with that unit, he was promoted to brigadier general on August 20, 1861, and ordered to report to Washington, D.C. While in transit, his orders were changed to report to Cape Hatteras Inlet, North Carolina. Maj. Gen. George B. McClellan intervened with the Secretary of War to get his orders changed once again, assigning him to the newly formed Army of the Potomac. His first assignment was with a board that examined the qualifications of volunteer officers, but he soon was given command of a brigade of Pennsylvania Reserves.
As McClellan's army moved up the Virginia Peninsula in the 1862 Peninsula Campaign, Reynolds occupied and became military governor of Fredericksburg, Virginia. His brigade was then ordered to join the V Corps at Mechanicsville, just before the start of the Seven Days Battles. The brigade was hit hard by the Confederate attack of June 26 at the Battle of Beaver Dam Creek, but their defensive line held and Reynolds later received a letter of commendation from his division commander, Brig. Gen. George A. McCall.
The Confederate attack continued on June 27 and Reynolds, exhausted from the Battle of Gaines' Mill and two days without sleep, was captured in Boatswain's Swamp, Virginia. Thinking he was in a place of relative safety, he fell asleep and was not aware that his retreating troops left him behind. He was extremely embarrassed when brought before the Confederate general of the capturing troops; D.H. Hill was an Army friend and colleague from before the war. Hill allegedly told him, "Reynolds, do not feel so bad about your capture, it is the fate of wars." Reynolds was transported to Richmond and held at Libby Prison, but was quickly exchanged on August 15 (for Lloyd Tilghman).
Didn't he also turn down command of the Army of the Potomac which then went to Meade?
Would have to check things but I'm fairly certain one of my books, think My Brother's Keeper but it may be Civil War Blunders, Strange Tales of the Civil War, or More Strange Tales of the Civil War that has the story of Reynolds capture in it. Might be one of Garrison's books, but seems to me it's one of these four.
Ok, only partially went through my books last night, primarily through the four (I'll be honest, folks, I checked the indices of the four I mentioned above for any mentions of John Reynolds and then looked up each to see if it was the story of his capture, it's still possible it could be in there and the page/pages not listed) I figured would have the story as well as some of Garrison's books and a few others. Found it in Armchair Reader: Civil War. Now according to this book Reynolds got separated from his men and took refuge in Boatswain's Swamp with the intention of getting some rest before trying to relocate his men and rejoin them. Just how true this is I can't say.