The rave was shut down on Thursday after several controversies and amid anger from locals.
Authorities have broken up a huge illegal rave that brought young people from across Europe to central Italy.
Up to 10,000 people are believed to have attended the week-long party on the shores of Lake Mezzano, between the Italian regions of Lazio and Tuscany.
But the event was brought to an end on Thursday after several controversies and anger from local residents and councillors.
One man drowned and at least four people have been hospitalised with alcohol-induced comas since the rave began on Friday.
Two other young people were admitted to hospital on Thursday in a state of "agitation" after reported drug use.
Police from the nearby city of Viterbo confirmed the unauthorised party had ended and more than 2,000 people in attendance had been identified. Local authorities had previously called on Italy's Interior Minister Luciana Lamorgese to step in.
"The area has been liberated," said the mayor of nearby Valentano, Stefano Bigiotti. "There is no longer anyone at the site. I can only express satisfaction."
Health officials had voiced concern that the mass gathering could lead to an increase in local COVID-19 cases.
"The situation is out of control, no negotiation is possible, public order must be restored, people identified and the responsibility for such a gathering must be established," said Lazio regional health councillor Alessio D'Amato.
Piles of waste were left in the countryside as citizens left the area on Thursday and authorities say they are working to remove the rubbish "as soon as possible".
Viterbo police said they had also seized two vans containing acoustic equipment as part of the operation on Thursday.
Prosecutors have also opened an investigation into the death of a 25-year-old man, whose body was found in the nearby Lake Mezzano.
The man -- who is reported to be an Italian resident from London -- had been seen going into the lake on Sunday night during the illegal rave.
The private area where the party took place has now been secured by police patrols to prevent people from returning.
Matteo Salvini, the leader of Italy's far-right Lega party had criticised the government for allowing the rave to take place and failing to prevent the "totally out of control" situation.