The phrase describing Gettysburg as the “high-water mark” of the Confederacy is famously attributed to Robert E. Lee.

After the defeat at Gettysburg, Lee understood that this battle signified the high point of Confederate military progress into the North. This notion conveys that the battle was a pivotal moment, after which the Confederate Army encountered growing difficulties and losses. Lee's recognition of this event underscored the importance of Gettysburg within the larger framework of the Civil War, emphasizing its influence on the Confederate effort.