Park Rangers say it's located on the northern edge of Sioux City but on the park's southeast edge.
The Iowa Natural Heritage Foundation, who helped coordinate the fundraising, recently transferred the land to the Iowa Department of Natural Resources to own and manage.
Park officials are currently working to plant some of the land back into native prairie, but it is open for people to explore.
"If it was in private property or developed, it would change the view shed from a lot of our vantage points. So it's part of the Loess Hills and it's identified as a special landscape area, so we want to see it protected for a long time," said Kevin Pape, Stone State Park Ranger.
With the new addition, the park is now a little over 1,500 acres.