Campaigners angry at plans to save £2m by cutting library services have marched through Lincoln city centre.
Lincolnshire County Council is looking at reducing the number of libraries under the authority's control from 47 to 15.
Those against the plans said the cuts would leave many residents, particularly the elderly, without access to a library.
The council said 82% of people in Lincolnshire were not active borrowers.
About 250 people joined the protest march, which started at Castle Square at 12:00 BST.
Organisers said 20,000 people had signed a petition against the council's plans.
"We want to send a clear message to the council - hands off our libraries," said Nick Parker, from the Lincoln and District TUC.
"The turn-out shows how loved our library services are and we are committed to fighting to keep them in public hands, run by public servants and not by volunteers."
Up to 170 jobs could go if the proposals are approved, as the plans include reducing the number of posts from 298 to 128.
The council has indicated local communities could take over the running of some libraries.
Councillor Nick Worth, the county council's executive member for libraries, said: "Despite the continuing decline in usage, we know there are still people who are passionate about libraries."
A public consultation on the plans runs until 30 September.