The Usher Gallery and The Collection in Lincoln, as well as Gainsborough Old Hall, are on all on the list to be changed, under council plans.
A report set to go before the executive has outlined final recommendations for the future of heritage services in the county.
Senior county councillors are set to make a decision on the proposals at an executive meeting in September.
The county council is looking to shake up services in an effort to save money. The council needs to make £30 million worth of savings in the next three years.
As part of the plans, the authority wants to make The Collection into a heritage “supersite”, meaning it would tell a range of stories and exhibitions rather than just one story.
This would add to the current supersite at Lincoln Castle and make the service “flexible”.
Alongside this, three microsites at Museum of Lincolnshire Life, Battle of Britain Memorial Flight Visitors Centre and Heckington Windmill would be “enhanced” by the new supersite.
Finally, the Usher Gallery would no longer be operated by the county council.
Instead, the authority will find other uses for the building and focus on exhibitions being held at The Collection supersite.
Therefore, the building would be handed over to another organisation to operate.
The plans for heritage services are as follows:
Usher Gallery – The council has proposed using the gallery as a events venue and coroners court and handing over the service to a third party.
The Collection – Carry out work to the building to create “flexible space” in order to display a range of art and archaeology exhibitions.
Gainsborough Old Hall – Terminate the lease on the hall which ends in October 2020. The county council will stop managing and operating the site and hand it over to English Heritage.
Discover Stamford, Ellis Windmill, Burgh le Marsh Windmill and Alford Windmill – The county council will look to hand responsibility of these sites to another organisation.
Museum of Lincolnshire Life, Battle of Britain Memorial Flight Visitors Centre and Heckington Windmill – All will be retained by the county council.
County councillors said that heritage services need to “offer more” and become “more commercially minded”.
Meanwhile, the proposals to change the Usher Gallery have caused controversy with the City of Lincoln Council calling on the county council to “reconsider” the plan.
The plans have also seen demonstrations from Save Lincoln’s Usher Gallery campaigners.
The city council owns the Usher building, which is leased and managed by the county council.
County council leader, Martin Hill, said the authority would still listen to other organisations ideas for the Usher.
“If city council have got better ideas, fine, we’ll let them do it,” he said.
“We’re not going to stay in their way.”
He added the changes were not all about saving money, with the Usher not getting as many visitors as the authority would like.
City council leader, Ric Metcalfe, said it would be inappropriate to discuss the authority’s response now.
“We have only just received the county council’s business case, when it was released to the public,” he said.
“It would not be appropriate to discuss this further until we’ve had time to digest their reasoning for walking away from an agreement that has stood for 45 years.
“As stated previously, we will respond in full once we’ve fully read the report.”