From October 2015 to September 2016, 197 young offenders either left custody, received a non-custodial conviction or received a caution. Of those, 102 committed a proven reoffence within a year.
Each reoffender committed an average of 4.8 offences within this period.
The 197 young offenders, aged under 18, also had 666 previous convictions between them.
In England and Wales, 42% of juvenile offenders committed another crime within a year, committing an average of 3.9 offences each.
The Ministry of Justice has cautioned that, since the figures only measure offences resulting in convictions or cautions, this could be a significant underestimate of the true level of reoffending.
Across England and Wales, juveniles are more likely to reoffend than adults. In Northumberland 26% of 2,015 adult offenders reoffended over the same period. Nationally, 29% of adults reoffended.
Youth justice practitioner on the Law Society criminal law committee, Greg Stewart, said that the way that juvenile crime is handled could be behind high youth reoffending rates.
According to Mr Stewart, who has been a practising defence lawyer for 25 years, children tend to only appear in court for more serious crimes, rather than minor misdemeanours.
He added: "As a result, those young people who are left still offending are the 'kernel' of offenders, often with complex and compound issues and serious problems at home and school."
Mr Stewart said that budget cuts to local youth programs have also contributed to the problem.
He said: "The savings that will have been made by the reduced charging rates are not being reinvested in rehabilitating the more vulnerable repeat offenders."
The Standing Committee for Youth Justice, a multi-member organisation with members including Barnardo's and the NSPCC, says that the harsher the punishment, the more likely under-18s are to reoffend.
Deputy chair of the committee Penelope Gibbs said: "If we want to reduce the reoffending of children we need to try and keep them out of the formal criminal justice system and out of prison.
"We instead need to address the trauma, mental health problems and behavioural difficulties which lead to them committing crime in the first place."
Rory Geoghegan, head of criminal justice at independent think-tank the Centre for Social Justice, said that if a young person ends up in the criminal justice system, rehabilitation programs that foster strong community links can also prevent reoffending.
He said: "We can make better use of the time served on a sentence by plugging young people into positive and trusted networks and organisations, such as community centres and youth organisations."