State Route 171 (SR 171) is a primary state highway in the U.S. state of Virginia. The state highway runs 11.19 miles (18.01 km) from SR 143 in Newport News east to a dead end at the Back River in Poquoson. SR 171 connects Poquoson with Interstate 64 (I-64), U.S. Route 17 (US 17), and Newport News via the York County community of Tabb.