It has reached an agreement to purchase and protect 78 hectares in the upper reaches of the Percival River.
Conservancy officials say the land is very close to almost 85 hectares of protected property they already own in the area.
"I like to think of it as a property that is full of natural capital because it is a forest and wetland complex, and specifically salt marsh," said Julie Vasseur, the program director for the conservancy.
"Both forest and salt marsh are really good at absorbing carbon dioxide. They store it in the forest itself so it actually pulls carbon dioxide out of the atmosphere."
Vasseur says the Nature Conservancy is asking the public, interested groups and companies to help them raise the remaining money needed.
Once the sale goes through, the land will be protected from development, but anyone will be able to go on the property to hike, bird watch or take photos.