The woodland reserve is part of the Millington Wood and Pastures Site of Special Scientific Interest. This beautiful ash wood occupies Lily Dale and dates back nearly 1000 years to 1086. Lily Dale is a typical dry valley of the Yorkshire Wolds, and has the distinctive features of a chalk karst landscape. These deeply incised and branching Dales around Millington are some of the finest examples in England that remain undisturbed from development. The wood was a commercial forestry in the 1960s when many ash trees were replaced with beech and Norway spruce. A small area of the ash woodland was left untouched, and is now one of the best ancient ash woods in the Yorkshire Wolds.
Millington Wood is special in all seasons, with scented carpets of ramsons and bluebells in spring, or leaves turning in autumn, with panoramic views across the colourful treetops. Many species are locally or nationally rare and a spring walk through the bluebell-carpeted woodland with the pungent smell of wild garlic (ransoms) is a great experience. The main ride is beautiful in summer, with the stunning bellflowers towering above the flower filled verges. Giant bellflowers can grow up to five or six feet in summer.