Important dates in U. S. history By 102311@students.mentorschools.org 1776 Declaration of Independence Declaration of Independence 1790 Whiskey Rebellion 1803 Louisiana Purchase 1815 Battle of New Orleans 1823 Monroe Doctrine 1829 Era of the Common Man 1848 Treaty of Guadalupe Hidalgo 1857 Dred Scott Decision 1863 Battle of Gettysburg 1876 Battle of the Little Bighorn