The construction of Terwilliger Boulevard was first mentioned in landscape architect John C. Olmsted's 1903 report to the Portland Park Board. Olmsted envisioned a comprehensive system of parks and parkways for all of Portland - with Terwilliger Blvd, or South Hillside Parkway as he called it, becoming the principal pleasure drive leading south from the city. John and his stepbrother, Frederick Law Olmsted, Jr., felt that boulevards and parkways were important additions to cities and added a feeling of civility to movement in an urban area. Of the four proposed parkway systems, Terwilliger is the only one completed for public use and utilized as envisioned by its planners.
The parkway got its name from the James Terwilliger family. James came to Oregon in 1845, built a log cabin at what is now SW First and Morrison St, and opened a blacksmith shop. He traded an eastside land claim for a horse, then traded that horse for 640 acres in Portland's west hills. In 1854, he, his wife, and some adjacent landholders donated a total of 10 acres that became the city cemetery. James died in 1892 and his heirs donated 19.24 acres in the form of a right-of-way through the Terwilliger property in 1909 as a part of the development of Terwilliger Blvd. The deeds stated that the donated land was intended to form part of the "Park and Boulevard System of the City of Portland."
Nothing was done to develop the parkway until 1909 when Portland lawyer Joseph Simon became mayor. By the end of his two-year term, the City had a design for the parkway, received gifts of land, purchased 2.84 acres and graded the portion between Hamilton and Slavin Roads. The 200-foot right-of-way was designed to ensure that no buildings would be built to obstruct the views. The formal dedication was held on August 4, 1914, and more than 200 autos paraded along the boulevard. The road was illuminated by electric lights, making the road seem "as light as day."
There was a great deal of discussion in 1917 regarding the surface of the roadway. It was not completely paved and the surface had begun to deteriorate. The boulevard had become one of the best routes between downtown and the southwest, and some people wanted to open Terwilliger to commercial traffic. The Oregon Railway and Navigation Company (which had donated 41.2 acres) and the heirs of James Terwilliger threatened to reclaim the right-of-way. The City attorney pointed out that much of the land was given expressly to "be used forever as a boulevard and parkway for the benefit and use of the public," and if the city failed in this or in the improvement of the parkway, the land would immediately revert to those granting the gift. The City paved the road within a year.
In 1959, the City created a special design zone for the parkway to retain its "heavily wooded character." In 1983 the City Council enacted the Terwilliger Parkway Design Guidelines and the Terwilliger Parkway Corridor Plan to preserve and protect this urban treasure from growing development.
A 1.93-acre parcel, located in the heart of Terwilliger Parkway, was owned by Charles and Thelma Norris. A longtime Portland resident and school teacher, Mrs. Norris was a charter member of the American Rhododendron Society. She and her husband planted dozens of rhododendrons on the property. When she died in 1992, she bequeathed the property to Portland Parks & Recreation.