For many visitors, the defense of the Union left on Little Round Top by Colonel Joshua Chamberlain and the 20th Main on July 2, 1863, has become a touchstone of the courage and determination of Federal forces at Gettysburg.  However, the stubborn defense of the Union right at Culp's Hill by Colonel David Ireland's 137th New York Infantry was at least as decisive, and may well have diverted a direct assault on the all-important Union supply line in the Baltimore Pike. On July 3rd, the battle for this section of Culp's Hill lasted seven straight hours - the longest sustained fighting at Gettysburg.  The tour starts at the Culp's Hill tower and covers about 3/4 mile of uneven terrain..