Veteran Lake County Board member Anne Flanigan Bassi won't seek re-election in 2012, she announced in an email to constituents and supporters.
Bassi, a Highland Park Democrat, has served on the board since 2002. The email, acquired by the Daily Herald, gave no explanation for her decision.
In a follow-up interview Friday, Bassi said she simply felt it was time to step down and let someone else have a turn representing the 23rd District.
She will finish her term, which ends in December 2012.
"I will continue to fight for the next 14 months for the issues that I believe make a difference to our residents and my constituents," Bassi said.
In her email, which also went to some county board members, Bassi called her political service "one of the most fulfilling activities of my life."
"I appreciate the trust and confidence you placed in me," she said. "I worked hard on your behalf, and together we made a difference."
Bassi ended the heartfelt email by thanking the other board members for their friendship and assistance.
"There are no adequate words to convey my gratitude," she said.
County board district boundaries will change for the 2012 election because of population changes recorded in the 2010 Census. Additionally, the board voted in June to reduce its size to 21 members, from 23.
Some Democrats said the changes unfairly targeted members of their party, potentially forcing some into primary election battles against each other.
Bassi was among the seven Democrats who opposed the new map. All 13 Republicans on the board and three Democrats voted for the plan.