Two separate legal challenges had been made against Northamptonshire’s plans to close 21 of its 36 libraries.
The changes would leave Northamptonshire with eight large and seven medium-sized branches, or one library for every 60,000 residents.
According to the all-party parliamentary group for libraries, the European average is one library per 16,000 people.
Northants council, which is technically insolvent, was told in February by its auditors, KPMG, that its proposed 2018-19 budget was not achievable.
On the evidence before me, I am not satisfied that the cabinet appreciated what they had to decide Justice Yip.
In a statement, the council said it was continuing to work closely with community groups following the judicial review judgement.
Northamptonshire leader Matthew Golby said he was pleased by the ruling: “The county council is committed to finding a way forward that is satisfactory and achievable for all parties. »