On December 28, Iowa becomes the twenty-ninth state.

The United States annexes Texas on December 29 and on the same day Congress admits it to the Union as the twenty-eighth state.

A series of anti-Catholic riots take place in Philadelphia between May 6 and July 7.

The Compromise of 1850 a series of five bills, is passed on September 9. The Compromise allows California to enter the Union as a free state, gives New Mexico Territory the option of allowing or outlawing slavery, and creates a new Fugitive Slave Law.