On the Republican side, House Speaker Becky Lockhart and Reps. Ronda Menlove, John Mathis and Jim Nielson and Sen. Stuart Reid have said they do not plan to seek re-election.
"I worked hard to represent the people and I'm very thankful for the opportunity to serve them. I'm so appreciative, so thankful just to be given that opportunity," said Cosgrove, who focused on child-safety issues and veterans issues during his time representing Murray.
Hemingway, a Millcreek Democrat who served in the Legislature for eight years, said that after retiring a dozen years ago it's time for him to enjoy his retirement.
"I'm done," Hemingway said Thursday.
Hemingway served on the committee that recently finished an investigation into former Attorney General John Swallow and said that was a highlight of his career.
"That will stand out forever. That was a piece of work," he said.
Fisher was appointed to fill a vacancy in her West Valley District in April 2005 after serving as a city councilwoman for a number of years.