According to data from the US BLS, the unemployment rate of New Hampshire was 3.3% (sa) in August, 2015. Among all New Hampshire counties, these 3 were among those with high unemployment rates (nsa): Coos (3.4%), Hillsborough (3.4%), and Rockingham (3.4%).

On the hand, the following three counties were among those with low unemployment rates (nsa): Grafton (2.4%), Sullivan (2.5%), and Merrimack (2.8%).

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

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