The numbers come from the state Employment Security Department's monthly report.
The jobless rate in Yakima County was 10.1 percent in March.
Kittitas County also saw a large drop in unemployment. Its jobless rate fell from 8.1 percent in March to 6.2 percent in April.
Both counties still have higher unemployment than the state average. Washington's statewide jobless rate was 5.6 percent last month.
These numbers are not seasonally adjusted.