Eleven people have been arrested after an illegal rave on farmland, Sussex Police said.
An estimated 200 people were at the event off Falmer Road in Brighton at about 03:00 BST on Sunday,
Police said they were unable to close down the gathering safely because of the time of night and road layout.
Nine people have been arrested on suspicion of causing a public nuisance, with two others held over drug driving and an assault.
Roads in the area were closed off to prevent more people arriving at the rave.