On June 3rd, 1863, Robert E. Lee began his risky venture into Pennsylvania-the Gettysburg Campaign had begun. Leaving A. P. Hill at Fredericksburg, Lee moved toward Culpeper Court House, the first stopping point along his invasion route. Having come to the conclusion that Lee was up to something, Hooker ordered Alfred Pleasanton, who had replaced George Stoneman the month before, to take his cavalry (plus one infantry brigade) to Culpeper and destroy whatever of the enemy he found there.
The 2nd MA was one of 2 regiments of the 12th Corps to be selected for the special mission. The other was the 3rd WS-both of Ruger's Brigade. Considering that Slocum's Corps was the smallest in the Army of the Potomac, and was considered by many in the Army as little more than an adjunct, it was a great honor for Ruger's (formerly Gordon's) Brigade and attests to the high reputation of both regiments. The rest of the ad hoc brigade were the 2nd & 7th WS, 33rd MA, 6th ME, and 86th & 124th NY. Capt. Daniel Oakey did not reckon the force to be more than 3,000 "as each regiment was thinned down by weeding out every man who could not be relied upon for a forced march."