The Narrow Neck Plateau, an eroded remnant of a sandstone layer situated at an elevation of 1,000 metres (3,300 ft) above sea level that is part of the Blue Mountains Range which is a spur line off the Great Dividing Range, is situated immediately south-west of Katoomba in New South Wales, Australia, located within the Blue Mountains National Park. The neck separates the Jamison Valley from the Megalong Valley.

The Blue Mountains are a mountainous region and a mountain range located in New South Wales, Australia. The region is considered to be part of the western outskirts of the Greater Sydney area. The region borders on Sydney's main metropolitan area, its foothills starting about 50 kilometres (31 mi) west of centre of the state capital, close to Penrith. The public's understanding of the extent of the Blue Mountains is varied, as it forms only part of an extensive mountainous area associated with the Great Dividing Range. As defined in 1970, the Blue Mountains region is bounded by the Nepean and Hawkesbury rivers in the east, the Coxs River and Lake Burragorang to the west and south, and the Wolgan and Colo rivers to the north. Geologically, it is situated in the central parts of the Sydney Basin.