Garret Mountain Reservation is significant for its association with the American Parks Movement and the Olmsted Brothers firm. The Passaic County Park Commission acquired most of the property in 1927. It was designed by the Olmsted Brothers firm and completed by WPA workers. The park opened to the public in 1931 and continues to embody key elements of the original design, characterized by picturesque meadows, curving pathways, scenic viewpoints, and water features.