1841 - President William Henry Harrison dies after one month in office, and is succeeded by Vice President John Tyler.
1845 - Potato crops fail throughout Europe. Approximately two million people will die in the resulting famine. The famine is especially hard in Ireland where potatoes are a major food crop, resulting in a wave of Irish immigration.
1846 - Failing in his attempt to purchase the New Mexico territory from Mexico, President James Polk orders Zachary Taylor to advance to the Rio Grande. Congress declares War on Mexico.
1848 - The Treaty of Guadalupe Hidalgo ends the Mexican War. Mexico gives up California and all land north of the Rio Grande, which makes up 35% of Mexico's total territory.
-
1849 - Kentucky native and Mexican War hero Zachary Taylor is inaugurated President.