[2] Tacoma's status as a major trading hub was greatly strengthened by the 1873 decision by the Northern Pacific Railroad to establish its western terminus at Commencement Bay.

Tacoma was chosen over other nearby cities such as Seattle for several reasons: Commencement Bay could dock more than 50 ships at a time, the harbor was deep enough for vessels of any draft, and there were miles of tideland waterfront available for expanded port facilities.

[2] The United States Army Corps of Engineers straightened the Puyallup River between 1948 and 1950, leading to litigation in the early 1980s over ownership of 12 acres of land formerly in the riverbed.

[5][6][7][8][9][10] The claims dated to the 1856 Medicine Creek Treaty and the Puyallup's 1856–1857 renegotiation of their reservation boundaries at Fox Island.

The reservation still exists legally and includes at least the Port's land between Hylebos and Blair Waterways and the entire city of Fife.

[11] Joint operations began with the formation of the Northwest Seaport Alliance on August 4, 2015, creating the third-largest cargo gateway in the United States;[12][13] by the end of the year, it reported more than 3.5 million twenty-foot equivalent units handled by the two ports, an increase of 4 percent.

[14] The port plays a large international trade role in the Pacific Northwest, and is a municipal corporation that operates under state-enabling legislation.