Areas of deterioration affecting the strength of Barney Bridge are to be repaired and the bridge repainted and re-waterproofed to help protect it from future damage.
The works are scheduled to take place from Monday, April 15 to Friday, July 5, 2019.
For the majority of that time, the bridge will be closed to traffic so motorists will be diverted via Metheringham, Woodhall Spa and Horncastle.
The bridge will remain open to pedestrians and cyclists.
Councillor Richard Davies, Executive Member for Highways, said: “It’s vital we make these repairs as soon as possible to ensure the bridge remains safe for people to use.
“The work is planned to start once everything is in place in April.
“That means we should be able to get it done before the busy harvest time.
“We realise there will still be significant disruption in the local area while the work is carried out, so we are looking at ways in which we can minimise the length of time the road is closed for.
“As always, we advise people to leave additional time for their journeys and use alternative routes wherever possible.”
For more on roadworks taking place across the county, click here