According to data from the US BLS, the unemployment rate of Connecticut was 4.5% (sa) in March, 2017. Among all Connecticut counties, these 3 were among those with high unemployment rates (nsa): Windham (5.3%), New Haven (5%), and Litchfield (4.8%).

On the hand, the following three counties were among those with low unemployment rates (nsa): Tolland (4.1%), Middlesex (4.2%), and New London (4.5%).

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

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