Colonel Stephen Watts Kearny's expedition to the Rocky Mountains was composed of five companies of the First Dragoons, one of two cavalry regiments in the United States Army. Other elements of the First Dragoons were scattered along the frontier from the Indian country along the Arkansas and Washita rivers to the Red River of the North, making it difficult to mobilize more than half of the regiment. Five companies, however, were enough to make the demonstration of force required to deter the Indians from any outbursts in the event of war with England or Mexico.

Specifically, Kearny's command was to gather information on the plains country, protect the emigrants on the Oregon Trail as far as the South Pass, and then swing southward to Bent's Fort so as to convoy the traders' caravans moving from Santa Fe to Saint Louis. He was also ordered to persuade the Indians to refrain from attacking the emigrant trains, by words if possible, and by convincing demonstrations of military prowess if necessary. In this sense the dragoon reconnaissance was an experiment to test the value of occasional cavalry forays as a means of keeping peace among the Indians as well as an attempt to find an alternative to the chain of forts recommended by Fremont as nucleii for settlement and stepping stones for continental expansion. A patrol in force representing strictly military considerations was the policy advocated by a number of professional soldiers, including Kearny himself. It followed the example of the French Army in Algeria, which was concentrated in the large population centers, leaving the hills and desert to the native tribes, except when caravans passed through. The contrast between the points of view of Kearny and Fremont was representative not only of thedifferent objectives of military and civilian occupation but also of the fundamental difference between Fremont's optimistic view of the West as a garden inviting settlement and Kearny's pessimistic view of it as an uninhabitable desert.

Lieutenant William B. Franklin, the Topographical Engineer attached to the party, was fresh from West Point, where he had been first in the class of 1843. He joined Kearny's command ten days out of Fort Leavenworth with the necessary instruments to make his scientific reconnaissance.

The course followed by the soldiers was clearly marked by the wagon ruts of the emigrants bound for Oregon. They crossed the Little Blue, followed the Platte to Fort Laramie (sic), and continued on through Indian country to the South Pass, where they turned back. At Fort Laramie (sic) on a cold, drizzling morning, with the rain turning to sleet, Kearny held a grand parley with the Brule' and Oglalla bands of the Sioux. Despite the inclement weather, it was a successful pageant with colorful costumes, flags flying, and much loud firing of ceremonial cannons. After an impressive speech by Kearny,the Indians agreed to refrain from attacks on emigrant trains.

The the dragoon column swung southward along the Chugwater branch of the Laramie Fork on the eastern side of the mountain ranges. Another Indian council was held with the Cheyenne and Arapaho, and afterward the march continued via Cherry Creek and the Arkansas River to Bent's Fort. which was reached on July 20. Kearny wasted no time there, however, and left the next day on a rapid march for the regimental headquarters at Fort Leavenworth.

Lieutenant Franklin, as Topographical Engineer to the expedition, contributed a carefully drawn map of the country traversed. In part it duplicated the work of Fremont in 1843-44, and Franklin acknowledged the Fremont map as his source for the area between the Platte River and the South Pass. Franklin's map added new data, however, on the country between the Platte and the Arkansas. Also on his map was the suggestion that the Grand River flowed westward from the vicinity of Long's Peak into the Green River.