Interstate 285 (I-285) is an Interstate Highway loop encircling Atlanta, Georgia, for 63.98 miles (102.97 km). I-285 is also un-signed State Route 407, and is colloquially referred to as the Perimeter. Suburban sprawl has made it one of the most heavily traveled roadways in the United States, and portions of the highway slow, sometimes to a crawl, during rush hour.