Named for the U.S. Army's 42nd Rainbow Division that fought gallantly in World War I, Rainbow Beach & Park began as two separate municipal beaches. The first was established in 1908 by the Special Parks Commission, a city agency that studied open space needs and created parks, playgrounds, and beaches in densely- populated areas of Chicago. This small site at 79th Street and Lake Michigan was known as Rocky Ledge Beach. The name referred to the area's rocky terrain, and to the manmade limestone ledge that served as a shore promenade and provided protection from shoreline erosion. By 1912, the heavily-used beach had bathrooms and changing rooms. Illuminated by electric lights, the beach remained open until 9:30 p.m. for the benefit of working men and women.

In 1914, the city began efforts to expand the beach, and soon acquired land between 75th Street and Rocky Ledge Beach. The City Council officially named the new site Rainbow Beach in 1918. The smaller, adjacent Rocky Ledge Beach continued operating as a children's beach.

The two beaches were consolidated in 1959, when the Chicago Park District began leasing the site from the city. For many years the park lacked sufficient indoor recreational facilities, so in 1999 a large fieldhouse was constructed. Designed by David Woodhouse Architects, the fieldhouse takes full advantage of Rainbow Beach & Park's breathtaking views of the lakefront and skyline. 

Located in the South Chicago neighborhood, Rainbow Beach and Park totals 142 acres. Indoor amenities include a gymnasium, fitness center, and multipurpose rooms. Outside, the park offers a beach and comfort station, community garden, basketball/ tennis/ handball courts, baseball diamonds, and two playgrounds. Many of these spaces are available for rental including our fields, gymnasium and multipurpose clubrooms. Rainbow Beach is home to one of the most ecologically important natural areas in the city, Rainbow Beach Dunes.

Park-goers can participate in the Park Kids afterschool program, seasonal sports, arts & crafts, youth and adult fitness classes, Senior Club, Teen Club, cheerleading, and basketball leagues. During the summer, youth can participate in the Chicago Park District’s popular six-week day camp.

In addition to programs, Rainbow Beach Park hosts fun special events throughout the year for the entire family, such as holiday-themed events.