Jefferson National Expansion Memorial consists of the Gateway Arch, the Museum of Westward Expansion, and St. Louis' Old Courthouse. During a nationwide competition in 1947-48, architect Eero Saarinen's inspired design for a 630 foot stainless steel arch was chosen as a perfect monument to the spirit of the western pioneers. The Museum of Westward Expansion, located below the Arch, is as large as a football field and contains an extensive collection of artifacts, mounted animal specimens, an authentic American Indian tipi, and an overview of the Lewis and Clark expedition. Located just two blocks west of the Arch, the Old Courthouse is one of the oldest standing buildings in St. Louis, begun in 1839. It was here that the first two trials of the Dred Scott case were held in 1847 and 1850. Today, the building houses a museum charting the history of the city of St. Louis and restored courtrooms.

The Pony Express National Historic Trail was used by young men on fast paced horses to carry the nation's mail across the country, from St. Joseph, Missouri to Sacramento, California, in the unprecedented time of only ten days. Organized by private entrepreneurs, the horse-and-rider relay system became the nation's most direct and practical means of east-west communications before the telegraph. Though only in operation for 18 months, between April 1860 and October 1861, the trail proved the feasibility of a central overland transportation route, and played a vital role in aligning California with the Union in the years just before the Civil War. Most of the original trail has been obliterated either by time or human activities. Along many segments, the trail's actual route and exact length are matters of conjecture. However, approximately 120 historic sites may eventually be available to the public, including 50 existing Pony Express stations or station ruins.

The battle fought here on August 10, 1861, was the first major Civil War engagement west of the Mississippi River, involving about 5,400 Union troops and 12,000 Confederates. Although a Confederate victory, the Southerners failed to capitalize on their success. The battle led to greater federal military activity in Missouri, and set the stage for the Battle of Pea Ridge in March 1862. Wilson's Creek was also the scene of the death of Nathaniel Lyon, the first Union general to be killed in combat. With the exception of the vegetation, the 1,750 acre battlefield has changed little from its historic setting, enabling the visitor to experience the battlefield in near pristine condition.

George Washington Carver's boyhood home in Diamond, Missouri, consists of rolling hills, woodlands, and prairies. The 210 acre park has a 3/4 mile nature trail, museum, and an interactive exhibit area for students. The cultural setting includes the 1881 Historic Moses Carver house and the Carver cemetery.

Harry S Truman National Historic Site includes the Truman Home in Independence, Missouri, and the Truman Farm Home in Grandview, Missouri. Both units are within the Kansas City metropolitan area. Harry S Truman (1884-1972), 33rd President of the United States, lived in the Truman Home from 1919 until his death. The white Victorian style house at 219 North Delaware Street was built by the maternal grandfather of Bess Wallace Truman (1885-1982), and was known as the "Summer White House" during the Truman administration (1945-1953). The site also includes the two adjacent homes of Mrs. Truman's brothers, and, across Delaware Street, the home of the President's favorite aunt and cousins. Built in 1894 by Harry Truman's maternal grandmother, the Farm Home is the centerpiece of a 5.25 acre remnant of the family's former 600-acre farm. Mr. Truman worked the farm as a young man, from 1906-1917. It was here, said his mother, that Harry got his "common sense." Several outbuildings are also on the site.

Established as a unit of the National Park Service in 1990, the park commemorates the life, military career, and Presidency of Ulysses S. Grant, as well as his wife Julia Dent Grant. The site, also known as White Haven, consists of 9.65 acres holding five historic structures (main house, stone building, barn, chicken house, and ice house).