This resolution commemorates the 200th anniversary of Jefferson Barracks in St. Louis County, Missouri, which was established on July 10, 1826. It began as the Army's first Infantry School of Practice and remains the oldest operational military installation west of the Mississippi River , playing a crucial role in westward expansion and the authorization of the U.S. Regiment of Dragoons, the first permanent cavalry unit. Throughout its history, Jefferson Barracks served as a critical military hub, functioning as a rest and supply station during the Mexican-American War and growing into the largest military installation in the U.S. by the 1840s. During the Civil War, it became a major hospital and recruitment depot, treating over 18,000 soldiers, and later served as a significant enlistment and deployment center during World War I. After being decommissioned post-World War II, its facilities were transferred to the Missouri National Guard, and today it is listed on the National Register of Historic Places. It continues to serve as a county park, historic site, and museum district, while also remaining an active military installation for the Missouri Air and Army National Guard, alongside the Jefferson Barracks National Cemetery. The House of Representatives celebrates this milestone, commending the thousands who served and recognizing the enduring contributions of Jefferson Barracks to military innovation and national security. The resolution encourages continued investment in its preservation and acknowledges Missouri's ongoing role in supporting national defense through such vital facilities.