This site is supposedly near the clearing where W.C. Overton and Asa Lovejoy agreed to found a town in November 1843. The square itself is named for Hugh Donaldson O'Bryant, a pioneer who migrated to Oregon from Georgia in 1843. O'Bryant was a carpenter who showed his civic pride in 1850 when he founded Portland's first public library. He was elected as Portland's first mayor in the city's first election on April 7, 1851, by receiving 104 of the 222 votes cast.
In the early 1900s, the Rivoli Theater and the Basket Grocery were the two best known features on the block. Built by Robert S. Farrell, business and political leader and one of the founders of the Multnomah Athletic Club, the Rivoli Theater was famous for its vaudeville acts. At the beginning of World War II, with stage acts a thing of the past, it was renamed the Newsreel Theater. The grocery was one of the finest gourmet delicatessens in Portland for 50 years before it was closed in 1969.
In 1971 the property was donated to the city by Mr. and Mrs. William E. Roberts. Built mostly of brick and concrete, the square was designed by Donald Edmundson and Evan Kennedy of the Portland firm of Daniel, Mann, Johnson & Mendenhall, and was dedicated in December 1973. O'Bryant Square's dominant feature is a bronze fountain in the shape of a rose, fittingly titled Fountain to a Rose. It was made possible through a $28,000 bequest from Donald Card Sloan, who was a prime minister of the Royal Rosarians in 1953. Its inscription reads "May you find peace in this garden." The fountain is surrounded by 250 rose bushes and other plants. Beneath the fountain's jets an underground parking garage accommodates 90 cars, making it the first park with parking in the city. In 1976, O'Bryant Square received a national design award from the U.S. Department of Housing and Urban Development.