The site which now bears the name Cathedral Park is steeped in history. It is believed to be one of the 14 Lewis and Clark landing sites in the Vancouver-Portland area: William Clark and eight men camped there on April 2, 1806. This spot had been a fishing and camping site for many area Indian tribes. In 1847, the founder of St. Johns, James John, settled on the site and operated a ferry to Linnton across the Willamette River. In 1931, the St. Johns Bridge was built on the site with 400-ft towers and a main span of 1,207 feet. It is the only steel suspension bridge in Portland and is designated as an official historical landmark.

In the early 1970s, Howard Galbraith, the `honorary mayor` of unincorporated St. Johns, got tired of the junkyard state of the area under the eastern end of the bridge. He organized a drive that eventually raised $7.5 million to build a park. After eight years of community fundraising, combined with state, county and city funding, the park was dedicated at a community celebration on May 3, 1980. It got its name from a photo of the St. Johns Bridge by Al Monner that appeared on the front page of the Oregon Journal in 1968. Reference was made to its beautiful cathedral-like arches and the park found its name.