The Archive

Reference Library

The founding document as written, a plain overview of the seven Articles, and a glossary of archaic and legal terms.

Back to Landmark Legislation

Territorial Expansion & Native Policy

Louisiana Purchase Treaty (Ratification and Appropriations)

Enacted: 1803

Signed into law by

Thomas Jefferson

In brief

The Senate's ratification and Congress's appropriation of $15 million doubled the size of the country and established Congress's power to fund territorial acquisition.

The Act in depth

President Jefferson negotiated the purchase of 828,000 square miles from Napoleonic France despite private doubts that the Constitution authorized the acquisition of foreign territory. The Senate ratified the treaty on October 20, 1803, and Congress appropriated the $15 million purchase price shortly after. The transaction doubled the size of the United States, opened the Mississippi River to American commerce, and set the constitutional precedent that Congress may acquire and govern territory under Article IV — a power later exercised in Florida (1819), the Southwest (1848), Alaska (1867), and the insular possessions.

All Legislation