A local lockdown will be imposed on Preston at midnight tonight after a spike in the number of coronavirus cases.
New restrictions will ban households in the city from meeting indoors or in gardens.
Preston had been braced for the announcement since a rise in Covid-19 cases was confirmed last week.
Ministers also confirmed that the current restrictions on gatherings in Greater Manchester, Leicester, parts of West Yorkshire and East Lancashire will remain in place.
Wider restrictions in Leicester, Blackburn and Bradford will also continue.
The lockdowns will not be lifted until next Friday at the earliest.
Making the announcements, health secretary Matt Hancock said: “The past week has been difficult for many people in Greater Manchester, West Yorkshire and East Lancashire, and I thank everyone in these areas for their patience and willingness to follow the rules.”
He said official data did not yet show a decrease in the transmission of the virus, meaning ministers had no choice but to keep the current restrictions in place “to allow more time for the impact of this ban on indoor gatherings to be felt”.
The extension of the measures to Preston was “at the request of the local area”, he added.
“We are constantly examining the data on the prevalence of the virus in these areas, and we will review the measures again next week.
“As we continue to see rising rates of the virus across Europe, it is vital we take every precaution to protect our country. I urge everyone in these areas to follow the rules, get yourself a free test as soon as you get any symptoms, and isolate if NHS Test and Trace tells you to.”
The Lancashire Resilience Forum said: “Since the rise of cases was first announced last week, residents, communities and businesses have been asked to take extra precautions to reduce the spread of the virus.
“These extra precautions are now mandatory and residents are still actively encouraged to get tested at the regional testing site based at Preston’s College if they are experiencing any symptoms of coronavirus.”
There were 61 new cases in Preston in the week to 4 August, the equivalent of 42.6 cases per 100,000 people – up from 21.7 per 100,000 in the previous seven days.
Earlier, the Office for National Statistics said that while national figures had suggested the percentage of those testing positive for Covid-19 had risen since the end of June, there was now evidence to suggest that trend may have levelled off.