Beltway 8 (BW8), the Sam Houston Parkway, along with the Sam Houston Tollway, is an 88-mile (142 km) beltway around the city of Houston, Texas, United States, lying entirely within Harris County. Beltway 8, a state highway, runs mostly along the frontage roads of the tollway, only using the main lanes where they are free: between Interstate 45 (I-45, North Freeway) and Interstate 69/US Highway 59 (I-69/US 59, Eastex Freeway); and between US Highway 90 (Crosby Freeway) and I-10 (Baytown-East Freeway). The main lanes elsewhere are the Sam Houston Tollway, a toll road owned and operated by the Harris County Toll Road Authority (HCTRA). East of Houston, the tollway crosses the Houston Ship Channel on the Sam Houston Ship Channel Bridge, a toll bridge; this forms a gap in Beltway 8 between I-10