The Ministry of Justice has announced Blundeston Prison in Lowestoft is to close by the end of the year, as part of a major re-organisation.
Justice secretary Chris Grayling said the category-C jail was in a poor condition and was deteriorating rapidly. He plans to replace a number of older sites with two new "super prisons" in England and Wales.
An illegal rave which started in Suffolk last night has been described as "potentially dangerous" by police.
Around 150 people attended the unauthorised event at Flixton Marsh Lane in Blundeston.
Police were alerted at 1.40am after reports of loud music and a number of vehicles were seen entering the site.
Officers are currently on site working to get music turned off and people off the site safely.
Superintendent Jon Dodman said: "The action taken to disrupt this event falls in line with our zero-tolerance approach to illegal raves, which are potentially dangerous and cause unnecessary damage and disruption."