Glenbrook is a township of the Lower Blue Mountains of New South Wales, Australia. It is located 63 kilometres west of the Sydney central business district, in the local government area of the City of Blue Mountains. As of the 2021 Australian census Glenbrook had a population of 5,078 people. Glenbrook lies between Lapstone and Blaxland at an elevation of 163 metres and is approximately a 50-minute drive from Sydney.