According to California's Employment Development Department, unemployment in Santa Clara and San Benito counties increased in June to a combined 6.1 percent, up from 5.6 percent in May.
The counties also added a combined 3,000 jobs in June, but because a growing number of people were looking for employment, the month's jobless rate still rose.
The department reported that June's job gains were half the average job growth Silicon Valley has seen for the past 18 years.
Layoffs at some of the region's largest companies combined with lost jobs in the construction and financial industries were mostly to blame for sending unemployment higher.
