People living in hamlets either side of a river could be asked to pay £650 a year to cross a bridge which has been free to use for decades.
The owner of the bridge, which connects Little Ouse in Cambridgeshire and Brandon Bank in Norfolk, said it was "actively seeking a solution to how it is best maintained and repaired".
Residents were "very angry about being asked for this money".
The owners said: "This is very much not a profit-making exercise."
The iron bridge dates from the 1970s and is owned by the South Yorkshire Pensions Authority (SYPA) along with the surrounding Waldersey estate.
Debbi-Jayne Challenger, of Little Ouse, estimated there were nearly 200 people in the vicinity who used the bridge, including farmers, who carried out the "odd repair".
She said cameras were mounted there early last year, some people received letters about using the bridge, and then at Christmas signs went up saying it was private land.
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"People are very angry about being asked for money," she said.
"Last week my friend got a letter from Bidwells, acting for SYPF, saying a cantilever bridge and lights were going to be erected.
"We've been told each household will have to pay £650 per year and £75 for a fob to use the bridge.
"They say it's for maintenance, but it's never been maintained since the 70s."
A spokesman from Bidwells said SYPA "understands its obligations as the owner of this now very-old private bridge and is actively seeking a solution to how it is best maintained and repaired".
He said meetings had been held "with a local users group" and one option was "transferring ownership of the bridge to them".
He added: "This is very much not a profit-making exercise. Whoever owns the bridge will need to build up a substantial sinking fund to ensure its ongoing safety.
"At some stage the bridge will need to be replaced and that fund would need to be available."