What is the term for an agreement between two or more states?

The term "Interstate Compact" refers to a formal agreement between two or more states in the United States. These agreements are typically used to manage shared resources, coordinate policies, or resolve disputes between states. Interstate compacts are a way for states to work together on issues that cross state lines, such as environmental regulations, transportation systems, and even criminal justice matters.

The U.S. Constitution provides a framework for these compacts in Article I, Section 10, which notes that states cannot enter into agreements with one another without the consent of Congress. This ensures that while states have the power to form agreements, they also maintain a level of oversight by the federal government. By entering into an Interstate Compact, states can create legally binding commitments to work collaboratively, which helps to address complex issues that require coordinated action among multiple jurisdictions.