NEW YORK (CNNMoney) -- The unemployment rate rose in 26 states last month, seven of which are key battleground states, critical in the presidential election.
Nationwide, the unemployment rate was 8.1% in August, but the job market differs dramatically from state to state. For example, in the swing state of Michigan the jobless rate rose to 9.4% in August, up from 9% a month earlier, a report from the Bureau of Labor Statistics showed Friday.
In Michigan, the biggest job losses occurred in manufacturing, trade and transportation.
Nevada, another election toss-up, registered the highest unemployment rate in the country, at 12.1%, up from 12% in July, as employers in the state continued to cut construction jobs.
North Carolina's unemployment rate ticked up a tenth of a percentage point to 9.7%, also as construction workers lost jobs.
Jobless rates in other battleground states -- including New Hampshire, Iowa, Pennsylvania and Wisconsin -- also rose.
In 12 states, the unemployment rates fell in August. Only two -- Colorado and New Mexico -- were swing states.
North Dakota continues to have the lowest unemployment rate in the country, at 3%. Polls show that state is leaning in favor of Republican candidate Mitt Romney. A rapid boost in energy jobs related to fracking means the state is adding jobs at rate far faster than its population growth.
The 12 swing states in the presidential election are considered to be Colorado, Florida, Iowa, Michigan, North Carolina, New Hampshire, New Mexico, Nevada, Ohio, Pennsylvania, Virginia and Wisconsin.