Interstate 520 (I-520) is a 23.50-mile (37.82 km) auxiliary Interstate Highway that encircles Augusta, Georgia and North Augusta, South Carolina as a three quarter beltway around the western, southern and eastern parts of the Augusta area. It begins at Interstate 20 in the northwest part of Augusta, and ends at Interstate 20 in North Augusta, South Carolina. I-520 is also known as Bobby Jones Expressway in Georgia and Palmetto Parkway in South Carolina. In Georgia, the road is unsigned State Route 415.

Interstate 520 begins at Interstate 20 in the northwest part of Augusta, and hooks around to the south and then east, crossing the Savannah River and crossing the Georgia — South Carolina state line before heading to the north to meet back up with Interstate 20. Its terminus is at Interstate 20 in North Augusta, South Carolina. The westernmost three miles are three lanes in each direction, with the remainder of the interstate having two lanes in each direction.

In Georgia, I-520 is named the Bobby Jones Expressway for golfer Bobby Jones; in South Carolina it is named the Palmetto Parkway for the sabal palmetto, the state tree. I-520 loses its state route designation in South Carolina, as it does not co-number its interstates with state highway numbers.

Although undesignated, the Bobby Jones Expressway continues north of I-20 in Georgia to have an interchange with Scott Nixon Memorial Drive and is designated as Georgia State Route 232.

I-520 was constructed in stages, with the first opening in 1980 between I-20 in Augusta and Doug Barnard Parkway (exit 10). The section between Doug Barnard Parkway (exit 10) and Laney-Walker Boulevard (exit 16) opened in July 1998. On June 22, 2004, the section between Laney-Walker Boulevard (exit 16) and US 1/US 78/US 278 (exit 17) opened to traffic, with I-520 now in the state of South Carolina. Phase 2 of the Palmetto Parkway stretching from Exit 17 to I-20 in North Augusta, South Carolina opened on December 17, 2009. With the completion of this final stretch I-520 is a loop from I-20, violating the numbering standard for Interstates, though existing in two states.

In accordance with MUTCD guidelines for auxiliary interstates, exit numbering is continuous across the state line and does not reset.