The local administration on Tuesday put Nilphamari under lockdown citing an increase in the number of coronavirus cases.
Deputy Commissioner Md Hafizur Rahman Chowdhury made the announcement in the afternoon after four new cases were reported in one week.
The lockdown was implemented since April 9 but was not officially announced to avoid spreading panic, he said.
Four coronavirus patients were found in Kishoreganj, Saidpur, Dimla and Jaldhaka upazilas, he said.
Meanwhile, seven more people died from coronavirus in Bangladesh in the last 24 hours till Tuesday, taking the death toll in the country to 46.