North East Lincolnshire Council said it had by far the biggest week on week increase in COVID-19 cases.
Some 1,037 residents have had a confirmed diagnosis of COVID-19 (based on pillar 1 and 2 testing), which is an increase of 419 cases over the last week.
The last three weeks have seen a doubling in new cases every six days and a forty-fold increase in the seven day rate of infection since the start of September.
However, its rate remains lower than the Yorkshire & Humber. South Yorkshire is moving into tier 3 (very high) restrictions from Saturday.
North East Lincolnshire is currently in the medium risk (tier 1) category, alongside Lincolnshire and North Lincolnshire.
The cumulative rate of COVID-19 infection in North East Lincolnshire is 596.6 per 100,000, which is a big increase from the previous week, when the rate was 382.3 per 100,000 (w/c October 5).
Analysis of 644 new cases in North East Lincolnshire confirmed since October 1 suggests an even spread across the working age population, with a steadily increasing number of cases now occurring in the young population.
There has been a growing number of cases in older people in the region since the beginning of October.
Geographically cases are occurring in all parts of the borough, but far more are now occurring in the Grimsby residential suburbs of Humberston, New Waltham, Freshney, Yarborough and Park wards.
North East Lincolnshire Council said the region is experiencing regular, small outbreaks in a range of settings including social clubs, spas and gyms.
However, the largest number of outbreaks are happening in workplaces and schools.
Hospitals and care homes
Northern Lincolnshire and Goole NHS Foundation Trust has 20 patients with confirmed COVID-19 in Grimsby Hospital (as of October 19).
This is the most since April and represents a substantial increase since the beginning of October.
There are a small number of cases in care homes currently. Many care homes are situated in the parts of the borough currently experiencing the highest number of cases.