In 1958, the City of Chicago purchased a quarter-acre property in the growing southwest side Archer Heights community from the Atchison, Topeka & Santa Fe Railroad. Although the city transferred the site to the Chicago Park District the following year, it remained undeveloped until around 1970, when the park district improved it with playground equipment, a basketball court, a curved walkway, and a short stone wall for seating. In January, 2000, the park was nearly doubled in size when the park district acquired the right-of-way of adjacent West 45th Street and South Hamlin Avenue. Officially designated Walnut Park in 1973, the park was one of many properties named for trees and plants at the time. The term "walnut" encompasses a genus of nut-bearing hardwood trees that include the European walnut, the butternut or white walnut, and the black or American walnut. The black walnut is one of the country's most valuable and sought-after timber trees. Its fine-grained, dark-toned wood has been used for high-quality American furniture and cabinetry since colonial times. When white settlers arrived in Illinois in the late 18th- and early 19th-centuries, the black walnut was common to the region's woodlands and along its river banks. Unfortunately, due to its usefulness, the tree became scarce within a few short decades.

Irma C. Ruiz park, formerly named Walnut Playground Park, is located in the Archer Heights community. The 0.53-acre park offers a small playground that was renovated in Fall 2015 as part of Mayor Emanuel’s Chicago Plays! Program. 

While there is no structured programming taking place at this location, we invite you to visit nearby Curie Park for sports, recreation and indoor swimming.