An interstate compact is an agreement between two or more states of the United States of America. Article I Section 10 of the United States Constitution provides that "no state shall enter into an agreement or compact with another state" without the consent of Congress. Frequently, these agreements create a new governmental agency which is responsible for administering or improving some shared resource such as a seaport or public transportation infrastructure. In some cases, a compact serves simply as a coordination mechanism between independent authorities in the member states. The lists below reflect this distinction.

Operating interstate agencies

• Atlantic States Marine Fisheries Commission (Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, Pennsylvania, Delaware, Maryland, Virginia, North Carolina, South Carolina, Georgia, and Florida)
• Bi-State Development Agency (Missouri and Illinois)
• Colorado River Compact (Colorado, New Mexico, Utah Wyoming, Nevada, Arizona, and California)
• Columbia River Gorge Commission (Oregon and Washington)
• Delaware River Port Authority (Pennsylvania and New Jersey)
• Delaware River Joint Toll Bridge Commission (Pennsylvania and New Jersey)
• Delaware River and Bay Authority (Delaware and New Jersey)
• Driver License Compact (all States except Georgia, Massachusetts, Michigan, Tennessee, and Wisconsin)
• Education Commission of the States (all States (except Washington), three territories, and Washington, D.C.)
• Emergency Management Assistance Compact (all States, plus Washington, D.C., Puerto Rico, and the U.S. Virgin Islands)
• Great Lakes Commission (Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, and Wisconsin)
• Gulf States Marine Fisheries Commission (Alabama, Florida, Louisiana, Mississippi, and Texas)
• Pacific States Marine Fisheries Commission (California, Oregon, Washington, Idaho, and Alaska)
• Port Authority of New York and New Jersey (New Jersey and New York)
• Washington Metropolitan Area Transportation Authority (Maryland, Virginia, and Washington, D.C.)
• Tahoe Regional Planning Agency http://www.trpa.org (California and Nevada)

Non-operating interstate compacts

• Northeast Dairy Compact (formerly set fluid milk prices for the New England states)

See also

• National Popular Vote Interstate Compact