On Wednesday, July 3, 1861, Union Major General John C. Frémont was named commander of the newly created Department of the West.
Frémont, headquartered at St. Louis, Missouri, would oversee military affairs for most of the country west of the Mississippi. He would replace Nathaniel Lyon as the top-ranking general in the area.
Frémont went to New York to buy weapons and supplies for his new command, but was not very successful. He left for St. Louis on July 21 and arrived four days later.