The block was originally bought in 1849 by Elijah Hill, a shoemaker. He paid $24 and a pair of boots. Later the Portland School Board purchased the site and opened Central School, Portland's first real schoolhouse, in 1858. It was moved to an adjoining street in 1883 to make way for the Portland Hotel which occupied the site from 1890-1951. The elegant hotel was torn down and for the next 30 years the site was a parking lot. In 1979, the City acquired the block from Meier & Frank Company who donated $500,000 toward creating an open space. In 1980, a national design competition was held to select a design team. The winning team was led by Portland architect Will Martin, who died in a plane crash not long after the square was dedicated. Located across from its namesake, the historic Pioneer Courthouse, Pioneer Courthouse Square officially opened April 6, 1984, sharing Portland's 133rd birthday.
The Square's features include the Waterfall Fountain, built of granite; sixteen columns with classical pillars topped with carved yellow roses on which crawl pink-and-green spotted bugs; and two brick amphitheaters which provide seats for events. Other pieces of artwork include J. Seward Johnson's Allow Me, a bronze statue of a man holding an umbrella. A signpost lets visitors know how far they would have to travel and in which direction to reach sights such as Walden Pond or Moscow's Red Square. And every noon, the Weather Machine performs, forecasting upcoming weather by displaying one of three metal figures amid a show of mist and flashing lights. Helia, a golden sun, indicates a clear, sunny day; Blue Heron predicts mist, drizzle, and changeable weather; and fierce, open-mouthed Dragon forecasts storms. This whimsical machine also tells the temperature.
In 2017, Pioneer Courthouse Square received major renovations with funding from the 2014 Parks Replacement Bond. Improvements included replacement of the failing waterproof membrane and deteriorated bricks, installation of a new HVAC system and other renovations to the office spaces under the Square, repairs to the stoa columns, and construction of a new all-user public restroom thanks to a small contribution from System Development Charges.