Who was George Meade's chief engineer who rushed troops to Little Round Top?

George Meade’s chief engineer who rushed troops to Little Round Top was Gouverneur K. Warren. His rapid recognition of the hill’s danger helped secure the Union army’s vulnerable left flank on July 2, 1863.

Warren had been appointed the Army of the Potomac’s chief topographical engineer and then chief engineer during Joseph Hooker’s reorganization in early 1863. At Gettysburg, Meade sent him to inspect the Union left. From Little Round Top, Warren noticed signs that Confederate forces were moving toward the largely undefended height and understood that its loss could expose the Union position.

Warren called for reinforcements, and troops from the V Corps were redirected to the hill. Brigadier General Strong Vincent’s brigade, including the 20th Maine under Joshua Lawrence Chamberlain, arrived before the Confederate attack reached the summit. The ensuing struggle became one of Gettysburg’s best-known episodes.

Warren did not personally command the infantry defense as a brigade or division commander; his crucial contribution was reconnaissance, judgment, and urgent coordination. Chamberlain is therefore a common answer to a different question: who led the famous 20th Maine defense?