The 200-year-old Union Chain Bridge, which links Hornciffe in Northumberland with Fishwick in Berwickshire, closed on October 1.
It will be shut for the next 15 months with no access at any time to vehicles, foot passengers and cyclists while contractors Spencer Group fully refurbish the bridge.
Diversion routes are signposted for both drivers and cyclists while the closure is in place.
Compounds are being set up on both sides of the border and the actual conservation work is due to start later in the month.
Cllr Glen Sanderson, leader of Northumberland County Council, said: “This is another key milestone for the bridge and signals the main works are about to get underway – something we’ve all been looking forward to for many months.
“While there is no access to the bridge we would thank people for their understanding while this magnificent structure is brought back to its former glory.”
Built in 1820 by Captain Samuel Brown, it is the oldest operational chain suspension bridge in the world still carrying vehicles.
The ambitious funding bid was put together by Northumberland County Council, Scottish Borders Council, Museums Northumberland and community group Friends of the Union Chain Bridge, following serious concerns about its condition of the world-famous structure.
The councils have committed £5.7m, while the project received £3.14m from The National Lottery Heritage Fund.
Other fundraising activities continue to be progressed by the Friends of Union Chain Bridge.
As well as conserving the historic structure, the project team has also developed interpretation proposals and a comprehensive programme of community engagement and education activities.
Rowan Brown from Museums Northumberland said: “We're delighted to have reached this milestone, despite facing the new challenges caused by the pandemic, and we're looking forward to working with the Spencer Group and our project partners to determine and deliver new Covid-19-safe learning and engagement opportunities for our communities in the coming weeks.”
The project team would love to hear from anyone who’s got a story to share about the bridge.