The Jefferson National Expansion Memorial is in St. Louis, Missouri

St. Louis, Missouri

St. Louis is an independent city on the eastern border of Missouri, United States. With a population of 319,294, it was the 58th-largest U.S. city at the 2010 U.S. Census. The Greater St...

, near the starting point of the Lewis and Clark Expedition

Lewis and Clark Expedition

The Lewis and Clark Expedition, or ″Corps of Discovery Expedition" was the first transcontinental expedition to the Pacific Coast by the United States. Commissioned by President Thomas Jefferson and led by two Virginia-born veterans of Indian wars in the Ohio Valley, Meriwether Lewis and William...

. It was designated as a National Memorial

National Memorial

National Memorial is a designation in the United States for a protected area that memorializes a historic person or event. National memorials are authorized by the United States Congress...

 by Executive Order 7523, on December 21, 1935, and is maintained by the National Park Service

National Park Service

The National Park Service is the U.S. federal agency that manages all national parks, many national monuments, and other conservation and historical properties with various title designations...

 (NPS).

The park was established to commemorate:

• the Louisiana Purchase
  Louisiana Purchase
  The Louisiana Purchase was the acquisition by the United States of America of of France's claim to the territory of Louisiana in 1803. The U.S...
  
  , and the subsequent westward movement of American explorers and pioneers;
• the first civil government west of the Mississippi River
  Mississippi River
  The Mississippi River is the largest river system in North America. Flowing entirely in the United States, this river rises in western Minnesota and meanders slowly southwards for to the Mississippi River Delta at the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains...
  
  ;
• the debate over slavery
  Slavery
  Slavery is a system under which people are treated as property to be bought and sold, and are forced to work. Slaves can be held against their will from the time of their capture, purchase or birth, and deprived of the right to leave, to refuse to work, or to demand compensation...
  
   raised by the Dred Scott case
  Dred Scott v. Sandford
  Dred Scott v. Sandford, , also known as the Dred Scott Decision, was a ruling by the U.S. Supreme Court that people of African descent brought into the United States and held as slaves were not protected by the Constitution and could never be U.S...
  
  .

The memorial consists of a 91 acres (36.8 ha) park along the Mississippi River on the site of the earliest buildings of St.