The Nonintercourse Act is the collective name given to six statutes passed by the United States Congress

United States Congress

The United States Congress is the bicameral legislature of the federal government of the United States, consisting of the Senate and the House of Representatives. The Congress meets in the United States Capitol in Washington, D.C....

 in 1790, 1793, 1796, 1799, 1802, and 1834. The Act regulates commerce between Native Americans

Native Americans in the United States

Native Americans in the United States are the indigenous peoples in North America within the boundaries of the present-day continental United States, parts of Alaska, and the island state of Hawaii. They are composed of numerous, distinct tribes, states, and ethnic groups, many of which survive as...

 and non-Indians. The most notable provisions of the Act regulate the inalienability of aboriginal title in the United States

Aboriginal title in the United States

The United States was the first jurisdiction to acknowledge the common law doctrine of aboriginal title...

, a continuing source of litigation for almost 200 years. The prohibition on purchases of Indian lands without the approval of the federal government has its origins in the Royal Proclamation of 1763

Royal Proclamation of 1763

The Royal Proclamation of 1763 was issued October 7, 1763, by King George III following Great Britain's acquisition of French territory in North America after the end of the French and Indian War/Seven Years' War...

 and the Confederation Congress Proclamation of 1783

Confederation Congress Proclamation of 1783

Confederation Congress Proclamation of 1783 was a proclamation by the Congress of the Confederation dated September 22, 1783 prohibiting the extinguishment of aboriginal title in the United States without the consent of the federal government...

.
The first four Acts expired after three years; the 1802 and 1834 Acts had no expiration.