Orange County's jobless rate for May jumped to 3.4% from 2.9% in April to hit its highest level since July, 1987.
But state labor analysts said the increase, which was in line with hikes for the rest of California's counties, was caused by a shift in the method used to generate unemployment statistics rather than by any significant change in the employment situation.
Statewide, the unemployment rate soared to 6.3% from April's 5.1%, and in Los Angeles County the rate was hiked to 5.2% from the previous month's 4.3%.
While the highest its been in 10 months, Orange County's May jobless rate still is considered to be a very low one. Most economists consider any area with an unemployment rate of 5% or less to have full employment.
Only two counties in the state, both in the San Francisco Bay area, had lower rates than Orange County for May: 3.2% for San Mateo County and 3.3% for Marin County.
Dan Johnson, state Employment Development Department labor market analyst for Orange County, said the prolonged period of low unemployment has caused a growing shortage of the workers needed to fill many of the lower-paid manufacturing jobs in the county and is beginning to force employers to raise their lowest wages in order to attract people.