According to data from the US BLS, the unemployment rate of Connecticut was 3.7% (sa) in September, 2018. Among all Connecticut counties, these 3 were among those with high unemployment rates (nsa): New Haven (3.8%), Hartford (3.6%), and Windham (3.6%).

On the hand, the following three counties were among those with low unemployment rates (nsa): Tolland (2.9%), Middlesex (2.9%), and Litchfield (3.1%).

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

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