A tourist attraction, which features one of the few remaining two-wheel water corn mills in the country is to be sold.
Eskdale Mill dates back to 1578
Cumbria County Council said it is selling the 16th Century Eskdale Mill, in Boot, because it was too expensive to maintain.
The council announced last month it was to sell the mill along with Talkin Tarn - which features 120 acres of woodland and a 65 acre lake - in the north of the county.
Eskdale Mill is believed to be one of the oldest working mills in England and opponents of the move do not want it to go to a private owner.
There are concerns the family who currently live in the mill cottage could be forced to leave.
Eric Robson, chairman of Cumbria Tourist Board: "There has been an appalling lack of consultation with local people, as far as I'm aware there has been none.
"It exactly the same as what happened in the north of the county with Talkin Tarn. People there are up in arms.
"The county council suddenly came up with a wheeze that they were going to flog it off, no consultation with the local people, and they are angry. We are also angry here.
Mr Robson added: "Our fear is that it will sell as a private residence. If that happens there is no guarantee at all that the mill would remain open to the public."
Roger Putnam, a member of the newly-formed local trust which wants to buy the mill, said a sale would deprive the valley of its tourism and education potential.
He said: "To put this on the open market is clearly the wrong way of going about things.
"If it is to be divested by the county council, it should clearly be offered to bodies who are concerned to look after it, maintain it as a facility open to the public and to develop it and restore it."
Eskdale Mill and Heritage Trust, formed by local people, hopes to bid for the mill and keep it open.
Councillor Tom Stoddart said authority was selling the mill because it could not justify the maintenance costs.
He said: "The council has obligations to the rate payers in Cumbria to deliver the best services it can, in the most efficient manner, for the best possible price.
"Unfortunately, the Eskdale Mill is requiring continued investment... this investment has not been forthcoming in recent years."