Development of the park began in 1898, when the Monongahela Street Railway Company leased a tract of land to Anthony Kenny. A wooded section if the land, called Kenny’s Grove, had long been used by the people for picnics and family reunions. The railway company leased the land feeling that amusement parks might just be a passing fad. The name Kennywood, was actually chosen by a man named Andrew Mellon, who later served as secretary of treasury, and whose family held some stocks with the railway.

The company wanted to build a trolley park to help boost the park’s popularity and ridership in the evening and on weekends. During the summer and part of the fall, the trolley company encouraged its passengers to visit Kennywood to watch the park’s development.

Construction began immediately as a dance pavilion, casino (restaurant), and a building to house a merry-go-round soon flourished. The park soon bought a three-row merry-go-round from Gustav A. Dentzel of Philadelphia. Then, trees were planted throughout the park and an artificial lake (only 3 feet deep) was dug. The dance pavilion was done in a “Queen Anne” style. Its 120 x 70 square foot floor was said to have a mirror-like surface. The building also had a 15 foot wide promenade the encircled the building and was separated from the dance floor by a small railing.

In 1925, the park built a gigantic swimming pool. The pool was designed by Lynch Brothers, New Haven, Connecticut. It was 350 x 180 square feet, cost $150,000, and took 2,250,000 gallons of water to fill it. A 2,500 seat, colonial style pavilion was built over the dressing rooms. There was also a 25 foot wide, white sand beach that surrounded three side of the pool. It required 20 railroad carloads of sand to build it.