Cumbria Police have arrested five men and one woman in connection with non-recent physical abuse, sexual abuse and child neglect offences reported to have taken place at Underley Hall School, Kirkby Lonsdale.
The arrests were made in Cumbria, Lancashire and West Yorkshire.
Five of those arrested have been released on bail. One is still being questioned by police.
A further two men have been arrested in Cumbria in connection with the same reports.
The arrests have been made as part of Operation Tweed - an investigation that was launched by Cumbria Constabulary in July 2014.
Superintendent for South Cumbria, Rob O’Connor, said: “This continues to be a complex investigation with a team of dedicated detectives following a number of lines of enquiry. Detectives have diligently and painstakingly gathered and analysed a large amount of evidence and have traced and interviewed a significant number people, many of whom are now living in areas across the country and abroad.
“This investigative work continues on a daily basis, as would be expected by victims for a case so serious and far-reaching.
“Cumbria Constabulary are committed to dealing with all reports of abuse that have been made.
“It is never too late to report abuse, and all reports will be dealt with professionally and sensitively.”
Cumbria Police can be contacted on 101 or alternatively call Crimestoppers anonymously on 0800 555 111.