American College Arboretum is a 35-acre arboretum on the campus of The American College in Bryn Mawr, Pennsylvania, serving both as a campus garden and a public tree collection. Its development began in 1959 when the college started preserving trees on the property, and it was formally established in 1994. Over time, the landscape has grown into a collection of about 600 labeled trees representing many species. Notable features include a small valley with a pond, the Samuel Weese Conifer Collection, and the Margaret Bradshaw Sundial Garden, which add specialized plantings and distinct garden spaces to the broader arboretum.