Lastoursville or Mandji is a city in central Gabon, lying on the River Ogooué, the Trans-Gabon Railway and the N3 road. It was founded as a slave depot named Mandji, renamed Maadiville in 1883 and finally took its current name for François Rigail de Lastours in 1886. It grew around palm oil production and as an administrative centre, and soon became a major missionary centre. The town is also known for its caves.