The A and B Loop is a streetcar circle route of the Portland Streetcar system in Portland, Oregon, United States. Operated by Portland Streetcar, Inc. and TriMet, it consists of two services within the Central City that travel a loop between the east and west sides of the Willamette River by crossing the Broadway Bridge in the north and Tilikum Crossing in the south: the 6.1-mile (9.8 km) A Loop, which runs clockwise, and the 6.6-mile (10.6 km) B Loop, which runs counterclockwise. The services connect Portland's downtown, Pearl District, Lloyd District, Central Eastside, and South Waterfront, and serve various landmarks and institutions, including the Rose Quarter, the Oregon Convention Center, the Oregon Museum of Science and Industry (OMSI), Oregon Health & Science University (OHSU), and