The International Boundary between Canada and the United States is among the most unique and awe-inspiring international borders. Spanning a massive 8,891 kilometers (5,525 miles) across the land, waterways, and national parks, it is the longest undefended and demilitarized border in the world, a testament to the strong and enduring friendship between these two neighboring nations. The boundary stretches from the Pacific Ocean in the west to the Atlantic Ocean in the east, crossing through four Canadian provinces and thirteen US states, encompassing a vast array of geographical features, including mountains, forests, lakes, and rivers. Despite its length and complexity, the International Boundary is managed harmoniously through a variety of mechanisms, including treaties, joint commissions, and friendly collaboration between the governments of Canada and the U.S. This unparalleled cooperation has allowed millions of people to cross the border each year for both business and leisure, forging strong bonds between the two countries and facilitating the free movement of goods and ideas. The International Boundary is a shining example of how two neighboring nations can live together in peace and prosperity while respecting each other’s sovereignty and unique cultural identities.