The Bells Line of Road (State Route 40) is a major road in New South Wales and runs from North Richmond on the North-Western outskirts of Sydney to Bell in the Blue Mountains where it becomes Chifley Road.

The route was discovered in 1823 by Archibald Bell Jr but was rarely used until World War II. The road was improved between 1939 and 1949 as it was seen by the government as being an alternative to the Great Western Highway and could be used for war efforts.

Today, the route is still used as an alternate route across the Blue Mountains and is also a popular tourist drive