Captain Kearny served through the war, and on the reductions of 1815 and 1821, was retained in the service with his old grade and rank. In 1823 he received the usual brevet for ten years faithful service, and was assigned to the command of the beautiful post of Bellefontaine, near St. Louis, and in that year accompanied Brigadier General Atkinson in his famous expedition to the Upper Missouri. This was before the introduction of steamboats into those waters, and the expedition was one of the most tedious imaginable. The boats were necessarily to be propelled by poles and oars against the rapid current of the Missouri, and not unfrequently by the tedious process of _cordelling_. This is done by extending from the capstan of the boat a cable, which is made fast to the shore, and thus the vessel must carefully be wound up until the rope is exhausted. Then a new rope is stretched, and the same tedious process undergone. Often, when in the midst of _rapids_, the cable would break, and before the vessel could be brought up, a greater distance than had been gained in a week would be passed over. In the course of two years they reached the Yellow Stone river, twenty-two hundred miles above St. Louis, and displayed the colors of the 1st and 6th infantry where the United States flag had never been seen before. The Sioux, the Pawnee, the Mandan, and Arickra, were made acquainted with the government, of which before they had but a vague knowledge, and the vast resources of that immense country for the first time revealed to the nation. On his return Major Kearny received a full majority in the third infantry, and was removed to a new sphere, to the southern extremity of the Indian territory. While major of this regiment he established the post of Towson, on the banks of Red River. To reach this place, easy of access as it is at present, it was necessary to pass through what was then a wilderness of prairie, but which to the soldiers inured to the incessant storms of the Upper Missouri, seemed almost an Arcadia. After crossing the northern tributaries of the Arkansas, they were in the midst of the range of the buffalo, and the countless herds of wild horses which then abounded even there. The latter, not unfrequently, amazed at the novel sight of the marching troops, would dash up, as if to charge the columns, pause with as much unanimity as if they acted by command, encircle it, and tossing their long manes and forelocks, hurry out of view. New objects continually met his gaze, and the information then amassed was among the most valuable ever collected under the auspices of the government. On this march Major Kearny was accompanied by his accomplished wife, a step-daughter of Gen. M. Clark, of St. Louis, whom, about the time of his promotion, he had married. With the third infantry Major Kearny remained until the Black Hawk war, when almost all the troops of the country were concentrated in the country of the hostile Indians.