Galloway and Southern Ayrshire (GSA), Scotland's first Unesco biosphere, will nearly double in size.
It occurs at the same time that a delegation of UN representatives announced the extension of its status for an additional 10 years.
In July 2012, the region was given the designation in recognition of its "world-class environment for people and nature.".
The phrase "fantastic array of landscapes, wildlife, cultural heritage, and learning opportunities" is used in the definition to acknowledge this fact.
More than 5,200 square kilometers, or 2,000 square miles, of the south-west of Scotland are covered by the biosphere.
With the addition of Robert Burns' birthplace, Alloway, and the Rhins of Galloway, which include Scotland's most southerly point, it will now nearly double in size.
According to Meriem Bouamrane, head of research and policy at Unesco, "The GSA Biosphere is an inspiring, globally recognized place to live, balancing conservation and sustainable use of biodiversity.
"We are overjoyed to announce today that we will be extending its designation status for an additional 10 years and expanding its geographic scope. ".
The definition takes into account the local environment, fauna, history, and educational opportunities.
It doesn't introduce any new laws or rules; instead, it promotes cooperation to build a "better future for people and nature.".
Conservation, education, development, and combating climate change are the four main goals.
One of hundreds of biospheres around the world, the Galloway and Southern Ayrshire site was the first in Scotland.