Poulton Library has closed its doors due to 'structural problems'.
Lancashire County Council announced on Tuesday that the library, on Blackpool Old Road, has been closed 'with immediate effect'.
It is not yet known when it will re-open.
Councillor Peter Buckley, Lancashire County Council's cabinet member for community and cultural services, said: "We've been monitoring the ceiling in the reception area of the library closely for a few weeks now.
"A detailed survey of the ceiling was able to happen yesterday, and following advice we were given, the decision was taken to close the library to allow remedial action to happen quickly and also because the safety of people using our libraries is an absolute priority. The library closed at the end of the normal opening hours yesterday.
"Although we haven't got a definite date for the library to reopen yet, we will do all we can to make sure that this happens as soon as possible. In the meantime, the nearest alternative libraries that people can use are at Thornton and Fleetwood.
"Customers will not be charged for any books that they are unable to return currently.
"I apologise for any inconvenience that this causes and we will keep people updated about the situation."
All library members can use their cards at any library in Lancashire. People have been advised to make use of services in the nearby Thornton, Fleetwood, Knott End and Kirkham libraries.