It's due to the coronavirus outbreak
In light of the country's move to the containment stage of Covid-19, which is in effect until March 29th, the city council have closed:
All branches of Cork City Council libraries,
The Cork City and County Archives,
The Cork Public Museum at Fitzgerald's Park,
St. Peter's on North Main Street,
And Elizabeth Fort.
Council offices will remain open during this time, however people are advised that access to the building is limited to the Anglesea Street entrance.