Boston Library will be shut for one week from next Saturday afternoon so maintenance and restructuring work can take place.
The project aims to make the library’s IT and data cabling a stand-alone system, separate from the rest of the County Hall complex.
The library will also use the opportunity to change the internal layout of the library and give it a new coat of paint.
Boston Library closes at 4pm on June 11 and reopen sat 9am on Monday, June 20.
Items due back during the closure period will be automatically extended until the reopening.
A library spokesman said: “There is never an ideal time to close a well-used facility like the Boston Library and inconvenience many of our users.
However, the long-term benefits and improved service through this essential maintenance, we hope, will outweigh the short-term disruption.”