| 1830 | The Book of Mormon published. |
| 1836 | Battle of the Alamo. Texas declares independence from Mexico. |
| 1837 | Steel plow patented. |
| 1840s | Practical mechanical reapers created. Fourierist communities founded. |
| 1841 | First wagon trains head west on Oregon Trail. Vice President John Tyler becomes president when William Henry Harrison dies. |
| 1844 | James K. Polk elected president. Samuel F. B. Morse demonstrates telegraph. |
| 1845 | Term manifest destiny coined. Texas enters Union as slave state. Potato blight spurs Irish immigration. |
| 1846 | Bear Flag Revolt. Congress declares war on Mexico. United States and Great Britain divide Oregon Country. |
| 1847 | Mormons settle in Utah. |
| 1848 | Treaty of Guadalupe Hidalgo. Oneida community organized. Seneca Falls convention. |
| 1849 | California gold rush begins. |
| 1850 | Utah Territory annexed. Railroads granted six square miles of land for every mile of track. |
| 1851 | Fort Laramie conference marks the beginning of Indian concentration. |
| 1855 | Massachusetts integrates public schools. |
| 1857 | Mormon War. |
| 1861 | California connected to nation by telegraph. |