The South Lake Union Streetcar, officially the South Lake Union Line, is a streetcar route in Seattle, Washington, United States, forming part of the Seattle Streetcar system. It travels 1.3 miles (2.1 km) and connects Downtown Seattle to the South Lake Union neighborhood on Westlake Avenue, Terry Avenue, and Valley Street. The South Lake Union Streetcar was the first modern line to operate in Seattle, beginning service on December 12, 2007, two years after a separate heritage streetcar ceased operations.