Eastlake is a neighborhood in Seattle, Washington, so named because of its location on the eastern shore of Lake Union. Its main thoroughfare is Eastlake Avenue E., which runs from Howell Street at the northeast corner of Downtown north over the University Bridge to the University District, where it connects to Roosevelt Way N.E. and 11th Avenue N.E. A second thoroughfare is Boylston Avenue E.; as an arterial, it parallels Interstate 5 for the four blocks between E. Newton Street to the south and E. Roanoke Street to the north, acting as an extension of Capitol Hill's Lakeview Boulevard E.

Lake Union is a freshwater lake located entirely within the city limits of Seattle, Washington, United States. It is a major part of the Lake Washington Ship Canal, which carries fresh water from the much larger Lake Washington on the east to Puget Sound on the west. The easternmost point of the lake is the Ship Canal Bridge, which carries Interstate 5 over the eastern arm of the lake and separates Lake Union from Portage Bay. Lake Union is the namesake of the neighborhoods located on three of its shores: Eastlake, Westlake and South Lake Union. Notable destinations on the lake include Lake Union Park, the Museum of History & Industry (MOHAI), and the Center for Wooden Boats on the southern shore and Gas Works Park on the northern shore.