Oak Ridges is an unincorporated community of Richmond Hill, Ontario, Canada, and has been part of the city since 1971. It forms the northern portion of the municipality's boundary, where it borders Aurora. Located about 20 km north of the northern border of Toronto and about 35 km from Downtown Toronto, it has a population of 18,520. The community developed around Lake Wilcox, the largest lake in the area, and has continued to expand slowly since its annexation by the Town of Richmond Hill.