Dec 2 US President James K. Polk announces to Congress that the United States should aggressively expand into the West, a widely held belief termed "manifest destiny" by newspaper editor John O'Sullivan
Dec 6 Alpha Sigma Phi Fraternity is founded at Yale College.
Event of Interest
Dec 17 German explorer Ludwig Leichhardt arrives in Port Essington after a nearly 4,800 km (3,000 mi) overland journey to explore Australia's Northern Territory
Dec 27 Ether 1st used in childbirth in US in Jefferson, Georgia