Parts of rural west Northumberland have seen the biggest spike in cases but there are also clusters of cases along the coast.
Data from Public Health England, published by Northumberland County Council, reveals the county-wide infection rate was 155.8 per 100,000 on December 1.
This compares to 168.6 per 100,000 on November 29.
There were 499 confirmed positive cases in the seven days up to December 1 compared with 540 in the week up to November 29.
Here are the 17 wards with the highest case numbers over the past week...