Daventry District Council is to contribute £200,000 towards the strengthening of a dangerous bridge to take 44-tonne vehicles after confusion about who was responsible.
The Hellidon Road Bridge, built in the 1890s over a now disused rail line in Charwelton, has been shut since June when it was discovered it was "unsafe".
The bridge is technically owned by Aero Research Partners who were willing to pay £150,000 for the strengthening along with the Historic Railways Estate - part of Highways England - who pledged £200,000, but the Department for Transport stopped this latter contribution and the district council stepped in.
Councillor David James said the closure had caused considerable inconvenience to residents, visitors to the area and businesses.
The Conservative-run council voted the £200,000 through despite criticism from Labour members who said it was an inappropriate use of local public finances.