The Thirty-Sixth Parallel North is a circle of latitude that is 36 degrees north of the Earth's equatorial plane. It runs across several countries, including the United States, Spain, and Japan. This parallel is significant in geography and is often used as a reference point for various mapping and navigation purposes. In the United States, the Thirty-Sixth Parallel North roughly marks the southern boundary of several states, including California and Arizona. It also plays a role in historical contexts, such as the division of territories during the Missouri Compromise in the 19th century, which aimed to balance the interests of free and slave states.