An international boundary is a defined line that separates two countries or territories. It marks the limits of each nation's jurisdiction and sovereignty, determining where one country's laws and governance end and another's begin. These boundaries can be established through treaties, historical claims, or negotiations. International boundaries can take various forms, including rivers, mountains, or artificial lines drawn on maps. They are crucial for maintaining order, security, and diplomatic relations between nations. Disputes over these boundaries can lead to conflicts, making their clear definition and recognition essential for peaceful coexistence among countries.