Cllr Mrs Nicola Clarke has resigned from her position as Lincolnshire County Councillor for the St Giles Division due to ill health.
A byelection is not required as the vacancy has occurred within six months of local elections.
Cllr Nicola Clarke said: “This has been a challenging time for me, but my health has deteriorated in recent months, and this is the right decision for everyone. It has been an absolute privilege to work with such honourable people and I will always look back on my time in office with fondness.
“I would like to thank all the Lincolnshire County Council and City Council officers, along with fellow councillors, who have helped me in my work over the last three-and-a-half years.”
Cllr Martin Hill, leader of Lincolnshire County Council, said: “Cllr Nicola Clarke has worked tirelessly for her St Giles community for the past three-and-a-half years, and championed residents’ interests on our adults and community wellbeing and public protection and communities scrutiny committees.
“Her knowledge and influence will be missed. I would like to thank her for her dedicated service to her community.”
In the interim period before local elections in May, St Giles residents who wish to raise concerns can contact Cllr Thomas Dyer.