The Fort Collins City Park Arboretum encompasses an eighty-five-acre public park established in 1912. Many mature American elms from the park’s early years form the backbone of the arboretum, which now includes more than 1,000 trees representing over 200 taxa. Over the past half century, an intentional effort has been made to curate and display a diverse collection of trees suitable for the Colorado Front Range, culminating in the park’s recognition as a certified arboretum in 2025. The City Park Arboretum will continue this legacy of excellence by being maintained as a space for both recreation and community engagement, offering opportunities to learn about the wide variety of trees that can thrive in the region.

The Fort Collins City Park Arboretum is home to several trees recognized as the largest of their species in the state of Colorado. Most impressive among these is an exceptionally large native lanceleaf cottonwood (Populus × acuminata) which has reached a diameter greater than 80 inches. This remarkable tree, along with others such as the champion European larch and northern red oak, is featured on the Fort Collins City Park Arboretum Tree Tour, available through the City of Fort Collins.