The Forty-Third Parallel is a circle of latitude that is 43 degrees north of the Earth's equatorial plane. It runs through several countries, including the United States, Canada, and parts of Europe and Asia. This parallel is significant in geography and is often used as a reference point for mapping and navigation. In the United States, the Forty-Third Parallel passes through states like Oregon, Idaho, Montana, and New York. It is also notable for its historical context, as it was used in the 19th century to define boundaries and territories, particularly in the context of westward expansion and settlement.