West Point was not merely a school for warriors. It was the pioneering institution of engineering and in the study of scientific subjects. The graduates of West Point would make numerous scientific discoveries in their journeys, especially the Topographical Engineer corps of which nearly all were graduates of West Point. Ingalls was posted west of the Mississippi, apparently Texas. At Fort Leavenworth in the Unorganized Territory he was promoted to 1st Lt. with the First Dragoons in 1845.
Dragoons are mounted infantry.
He may have been involved with the 1855 explorations made by Kearney and the topographical engineer William B. Franklin. Franklin was first in the West Point class of 1843, the same class as Ingalls and Grant. The outbreak of the Mexican War in 1846 would see Lt. Ingalls travel to Santa Fe, New Mexico with the 'Army of the West' under the command of Col. Stephen Watts Kearny.