Repair works to the historic monument, which was built between 1773 and 1780 and is situated overlooking Wentworth Woodhouse in Thorpe Hesley, begun this week.
The inside of the column has been closed to the public for the last 20 years, due to the eroded staircase and other structural issues.
The restoration project is set to be completed in Spring 2022 to repair the column and make it accessible to the public for the first time in more than two decades.
The restoration works will open up access to the top of the landmark.A quarter of a million pounds of the funding has come from Rotherham Council’s asset management and capital funding, and £207,377 has been put forward by Historic England.
The Fitzwilliam Wentworth Amenity Trust have also awarded a grant of £20,000 to support the restoration.
Leanne Buchan, Rotherham Council’s head of creative programming and engagement, said: “It’s great news that work is now underway on such an important monument in the borough.
“Keppel’s Column is such an important landmark within the local community but is in extremely poor state of repair due to significant structural issues including cracking and stonework erosion.
“The funding will enable us to preserve Keppel’s Column for the future and allow public access to it once again.”
The first stage of the work will be to clear the rubble from inside the column and begin work on the shaft by installing low level scaffolding to three meters high. Work will then begin internally repairing the stone steps.
The work is being undertaken by Aura who have been conserving many of the UK’s most important listed and historical buildings since 1973. They have worked on Grade I listed Wentworth Woodhouse as part of the first phase of works to protect significant architectural features and interiors.
They are supported by Soul Architects and structural engineers Mason Clark Associate and will be working closely with ecologist B J Collins Protected Species Surveyors to ensure minimal disruption to any nesting birds and local wildlife.