Walla Walla County's unemployment rate ticked up to 7.4 percent in May from April's preliminary 7 percent, according to monthly numbers the state Employment Security Department released in June.
The rate, however, remained below the county's 2011 yearly average of 7.6 percent.
Columbia County posted a 10.4 percent unemployment rate in May. Garfield County's rate matched Walla Walla's.
The preliminary statewide jobless rate was 8.4 percent. The number of people in the workforce without jobs in May totaled 292,600, down from 324,400 a year ago.
Employment Security economist Anneliese Vance-Sherman said May's rise in the jobless rate was caused primarily by more unemployed people re-entering the job market.
The report also looked at annual average wage growth. Those with jobs last year earned about 3.6 percent more money on average last year compared to 2010, the state reported. The average yearly wage last year was $49,894 last year.
The numbers include only wages covered by unemployment insurance.
According to state officials, much of the increase was driven by the 7.5 percent jump in the number of insured workers who earn more than $75,000 a year.
"Month to month, we've been seeing strong growth in industries that tend to offer above-average pay," Employment Security Commissioner Paul Trause said.
Industries with the highest wage growth were information (9.5 percent), company management (7.9 percent) and manufacturing (5 percent).
The average annual wage is used to calculate unemployment benefits for jobless workers.
The minimum weekly unemployment benefit, calculated at 15 percent of the average weekly wage, will increase by $5, to $143 for new claims opened on or after July 1.
At the same time, the maximum weekly benefit, calculated at 63 percent of the average weekly wage, will increase by $21, to $604.