Latest data from Public Health England, published by Northumberland County Council, puts the countywide rate at 654.4 positive cases per 100,000 population.
There were 2,096 confirmed new positive cases in the week to July 14.
That compares with 1,660 new cases in the week to July 7 when the rate was 518.3.
The data also reveals that the majority of positive cases were in the 10-19 age group, followed by those aged 20-29.
Here are the 29 areas of Northumberland with the highest rates...