In May 1846 when war was declared against Mexico, the U. S. Congress authorized the raising of 50,000 volunteer troops to supplement the regular U. S. Army. General Zachary Taylor was quickly inundated with volunteer soldiers arriving at Brazos Santiago, and was forced to place them in temporary encampments.

Camp Belknap, located on this site, was established in the summer of 1846. The camp was located on a long narrow rise of land, measuring about 2 miles in length and one-half mile at its widest point. It was the first high ground encountered after leaving the Gulf Coast. Thought to be the largest encampment for volunteer soldiers, troop estimates total 7,000-8,000 men including several regiments from eight states. Soldiers suffered exposure to the elements, unsanitary living conditions, overcrowding, biting insects, thorny plants, and disease. Many died a premature death, often resulting in one two two funerals daily. No enemy attacks took place despite one false alarm. During August and September most of the volunteers were moved upriver either to camps nearer Matamoros, or further to Camargo. The camp was completely empty by December 1846.