According to data from the US BLS, the unemployment rate of Connecticut was 3.8% (sa) in August, 2018. Among all Connecticut counties, these 3 were among those with high unemployment rates (nsa): New Haven (4.3%), Windham (4.2%), and Hartford (4.1%).

On the hand, the following three counties were among those with low unemployment rates (nsa): Tolland (3.3%), Middlesex (3.3%), and Litchfield (3.4%).

The chart and table below shows the unemployment rate (nsa) for each county.

You can see similar information by state for the United States.