Boab Prison Tree, Hollow baobab tree in the Kimberley, Western Australia

The Boab Prison Tree is a hollow Adansonia gregorii baobab standing about 7 km south of Derby in the Kimberley, Western Australia. Its trunk measures roughly 14 m around, and the opening into the hollow is about 1 m wide and 2 m high. The tree is fenced and still standing.

The Wyndham prison tree, 9 m tall with a 15 m girth, stands about 40 km south of Wyndham near the King River Road; the name Hillgrove Lockup is carved into its trunk. In 1890 police found the interior hollow and cut a cell of roughly 9 m², said to hold up to 30 people. Prisoners were usually held overnight while being taken to Wyndham for trial, and extra captives were chained to the outside. A second hollow baobab 7 km from Derby is reputed to have held Aboriginal people captured in the Kimberley in the 1880s, though a 1966 article found no reliable evidence for that use.

The Wyndham tree carries the name Hillgrove Lockup, an inscription still cut into its trunk, and was already a tourist attraction by the early 1900s. The Derby tree, by contrast, is fenced off and its use as a cell is disputed; a 1966 article found no reliable evidence for it. The hollow of the Wyndham tree was carved into a cell of about 9 m², said to hold up to 30 people.

The Wyndham tree stands about 40 km south of Wyndham, near Digger's Rest and the Moochalabra Dam, off the King River Road. The Derby tree, 7 km south of Derby, is fenced off, so visitors view it from outside the barrier. Both are reached by unsealed roads, and the Derby tree has a one-metre-wide, two-metre-high opening in its trunk.

The Wyndham tree was long known as "Hillgrove Lockup", an inscription carved into its trunk. In 1890 police found the interior hollow through openings near the upper branches and cut a cell of about 9 m², said to hold up to 30 people. Prisoners were usually held no more than one night while being taken to Wyndham for sentencing.