Western Sydney (WSROC) is a large region located west of the Sydney CBD, composed of eleven councils with a growing total population of more than 1.6 million people. Sydney Olympic Park is located here along with a collection of nature preserves and parks. The largest suburb contained in this region is Blacktown with a population of 39,000. The additional ten city councils include: Auburn, Bankstown, Blue Mountains, Fairfield, Hawkesbury, The Hills, Holroyd, Liverpool, Parramatta, and Penrith.