At Falling Waters, most of the Army of Northern Virginia escaped over the flooding Potomac on an improvised pontoon bridge on the night of July 13. However, the 42nd had halted about two miles from the bridge and the exhausted men had gone soundly to sleep that night. In his post-war reminisence, Andrew Parks relates, “When we woke…the Yankees were all around us." Davis' troops were attacked by two companies of the 6th Michigan Cavalry, and with their muskets rain-soaked, had to drive back the badly outnumbered cavalry using fence rails, axes and muskets as clubs. After a fighting withdrawal to the pontoon bridge, Davis crossed the Potomac just before the bridge was cut.

Falling Waters was yet another blow to the already weak 42nd, which had been decimated at Gettysburg. CSR analysis indicates that the 42nd had 5 killed, 6 wounded and 40 captured at Falling Waters. Parks states: “My regiment only had one hundred and forty five engaged and we lost forty five men in this engagement.” It is worth noting that the 42nd had almost six hundred men reporting for action on the first day at Gettysburg--the combination of the July 1 battle (including the railroad cut), Pickett's charge on July 3 and Falling Waters left only one hundred unwounded men in the regiment when it returned to Virginia July 14.