State Route 123 (SR 123) is a primary state highway in the U.S. state of Virginia. The state highway runs 29.27 miles (47.11 km) from U.S. Route 1 (US 1) in Woodbridge north to the Chain Bridge across the Potomac River into Washington from Arlington. SR 123 is a partial circumferential highway in Northern Virginia that connects Woodbridge in eastern Prince William County with the independent city of Fairfax and the Fairfax County communities of Vienna, Tysons Corner, and McLean, the last the home of the National Counterterrorism Center and the Central Intelligence Agency. The state highway also connects all of the major highways that radiate from Washington, including Interstate 95, I-66, US 29, US 50, SR 267, and the George Washington Memorial Parkway. Furthermore, SR 123 crosses another