Named after Keyport, New Jersey, in 1896, this small peninsula juts into Liberty Bay a few kilometers southeast of Poulsbo. The Navy established what was initially called the Pacific Torpedo Station on land that had previously been a pig farm, a detail that provided colorful nicknames in the station's early years. The base underwent a series of name changes as bureaucracies reorganized: Pacific Torpedo Station became Naval Torpedo Station, then Naval Undersea Warfare Engineering Station in the 1990s, then Naval Undersea Warfare Center Division Keyport, then Naval Sea Systems Command Keyport, and finally Naval Base Kitsap Keyport, aligning with facilities in nearby Bremerton and Bangor. Through every renaming, the core mission stayed constant: range torpedoes, repair them, and keep the undersea arsenal ready.

As the Cold War ended, budget reductions and multiple rounds of Base Realignment and Closure threatened Keyport's existence. The parent command in Newport, Rhode Island, claimed the engineering function for itself, at least on paper. But Keyport survived every closure round without shutting its gates. The cost was measured in people. The civilian workforce fell from roughly 3,500 in 1990 to 1,348 by 2005, a decline that rippled through the small surrounding community. One church serves Keyport: the Keyport Bible Church, established in the early 1900s, incorporated in 1926, with its building dedicated on May 2, 1937. It has expanded over the decades with classrooms and a multipurpose building, growing as the community around the base contracted.

Keyport's major attraction for visitors is the Naval Undersea Museum, which exhibits displays on undersea technology including the bathyscaphe Trieste II, a deep-sea submersible that descended to 20,000 feet. The museum sits outside the base perimeter and is free to the public, offering a rare civilian window into the technology of underwater warfare. Within the base itself, hiking trails on Radio Hill draw employees during lunch breaks, and a lagoon-side picnic area provides unexpected tranquility for a weapons facility. Recreational boaters, however, are warned to stay at least 300 feet from the production area. Like many American military installations, the base carries environmental scars: four areas require Superfund cleanup due to contamination from chlorinated hydrocarbons and PCBs. Poplar trees now grow over the former landfill as part of a phytoremediation program, nature slowly processing what industry left behind.