Old Mill Park was dedicated August 1, 1976 for historical and educational purposes. Containing original buildings, plantings, and artifacts, it has been designated a landmark by the City of Longmont. The Townley House (1871) guards the entrance to the park which houses the Affolter Cabin (1860), the Billings Cabin(1890), the Hauke Milk House (1860), and the Gildner Gazebo (1916). The Secor Centennial Garden and surrounding flower beds are beautifully maintained. There is also a stage and a picnic area.
The Park is open to the public from 10:00am to 6:00pm in the spring and summer months unless reserved for private events. This minipark was created by the St. Vrain Historical Society through the purchase of Townley House and the donation of the Secor Centennial Garden by Bill and Betty Jo Secor. Later purchases included adjoining properties on Pratt and Bross Streets. Each back yard was included in the park and some of the houses were retained as rental properties to help support the project.