Matlock and Wirksworth libraries have had their opening hours cut.
Derbyshire County Council is making the changes to save £1.76m from its cultural and community services department.
Matlock Library will close for two hours more a week – now closing on Mondays at 5pm.
Wirksworth Library will close for one and a half more hours a week – now closing at 5pm on Friday and opening a 9am on Saturday.
Bakewell opening hours will stay the same. It will now open from 9am every day but close at 1pm on Saturday.
A council spokesman said: “The county council has to save £90m over the next four years and our libraries have to contribute to these savings.”