Boolboonda Tunnel is an abandoned heritage-listed railway tunnel at Tunnel Road, Boolboonda, Bundaberg Region, Queensland, Australia. The tunnel is 192 metres (630 ft) in length making it the longest unsupported man-made tunnel in Queensland. Its construction represented an important engineering feat for rail transport in Queensland.It was built from 1881 to 1884 by O'Rourke & McSharry. It is also known as Boolboonda Railway Tunnel and SEQ-6Q 1. It was added to the Queensland Heritage Register on 24 September 1999.