The 36th parallel is a circle of latitude that is 36 degrees north of the Earth's equatorial plane. It is significant in geography and history, particularly in the United States, where it served as a boundary for various territories and states. This parallel runs through several states, including California, Nevada, Utah, and Colorado. In addition to its geographical importance, the 36th parallel has historical relevance, especially during the Missouri Compromise of 1820. This agreement aimed to maintain a balance between free and slave states, designating the 36°30′ parallel as the dividing line between these two types of states in the western territories.