I-705 is the shortest Interstate Highway in Washington, at 1.5 miles (2.4 km) in length, and primarily serves as a connector between I-5 and Downtown Tacoma.

[8] The freeway continues northwest onto Schuster Parkway, with a separate set of flyover ramps that end at an at-grade intersection with Stadium Way near the Old City Hall.

[13] In 1957, city officials from Tacoma proposed the construction of a downtown connector that would travel north from the Pacific Avenue interchange on I-5 (where SR 7 terminates) and improve vehicular access to the central business district.

The state Department of Highways had advanced their study into a downtown connector as part of SR 509 that would become an eventual freeway link.

[16]: 1–5  In 1968, the Department of Highways adopted the routing of a freeway into Downtown Tacoma along the western side of the City Waterway, to be constructed over railroad right of way.

[24] The offramp connecting southbound I-5 to East 26th Street was dedicated on April 21, 1983, a day before the Tacoma Dome opened to the public.

[28] The freeway was dedicated on October 17, 1988, with a parade and ribbon-cutting;[29] I-705 cost $102.3 million to construct and was the last new Interstate to be completed in the state of Washington.