List of highways numbered 521

The following highways are numbered 521:

Canada

 * Alberta Highway 521.svg Alberta Highway 521

United States

 * US 521.svg U.S. Route 521
 * MD Route 521.svg Maryland Route 521
 * County 521.svg County Route 521 (New Jersey)
 * OH-521.svg Ohio State Route 521
 * Ellipse sign 521.svg Puerto Rico Highway 521
 * SC-521.svg South Carolina Highway 521