4 Mar 1797: John Adams becomes President John Adams was inaugurated as the second President of the United States.
2
1798
7 Jul 1798: Quasi-War with France The U.S. entered an undeclared naval war with France, triggered by French seizure of American ships.
14 Jul 1798: Alien and Sedition Acts Congress passed a series of laws that made it more difficult for immigrants to become citizens and allowed the government to deport or imprison "seditious" persons.
3
1801
4 Mar 1801: Thomas Jefferson inaugurated Thomas Jefferson was sworn in as the third President of the United States.
4
1803
30 Apr 1803: Louisiana Purchase The United States purchased a vast territory from France for $15 million, nearly doubling the size of the country.
5
1804
14 May 1804: Lewis and Clark Expedition begins Meriwether Lewis and William Clark began their expedition to explore the newly acquired Louisiana Territory.
2 Dec 1804: Jefferson reelected Thomas Jefferson was reelected as President of the United States.
6
1807
2 Mar 1807: Act Prohibiting Importation of Slaves Congress passed a law prohibiting the importation of slaves into the United States, effective January 1, 1808.
7
1809
14 Jan 1809: Erie Canal construction begins Construction began on the Erie Canal, a major infrastructure project that connected the Great Lakes to the Atlantic Ocean.
8
1812
18 Jun 1812: War of 1812 begins The United States declared war on Great Britain over maritime rights and British support for Native American tribes.
16 Aug 1812: Surrender of Detroit American forces surrendered Detroit to the British, a major early defeat in the War of 1812.
