According to data from the US BLS, the unemployment rate of New Hampshire was 2.8% (sa) in May, 2017. Among all New Hampshire counties, these 3 were among those with high unemployment rates (nsa): Coos (3.6%), Hillsborough (2.8%), and Rockingham (2.8%).

On the hand, the following three counties were among those with low unemployment rates (nsa): Sullivan (2.2%), Merrimack (2.3%), and Grafton (2.3%).

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

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