The Boab Prison Tree, Derby is a 1,500-year-old, large hollow Adansonia gregorii (Boab) tree 6 kilometres south of Derby, Western Australia with a girth of 14.7 metres. It had been reputed to have been used in the 1890s as a lockup for indigenous Australian prisoners on their way to Derby for sentencing, but there is no evidence that it was ever used to house prisoners.