Orange County added jobs in March even as the local unemployment rate rose slightly for the month, according to the California Employment Development Department.

A higher rate despite more jobs often occurs when the pace of employment growth is less than the increase in the labor pool, which is often driven by overall demographic trends.

EDD data show 1,372,600 persons employed in non-farm jobs in OC in March, an increase of 3,100 compared with February. The county’s monthly unemployment rate rose to 8.1% from 8% the previous month.

The state employment picture also was mixed.

California’s unemployment rate rose to 11% from a previous 10.9%, according to the EDD, while nonfarm jobs increased by 18,200 jobs to a total 14,237,300. The state unemployment rate was 11.9% in March 2011.