The park, formally for NCR employees and retirees, is located next to NCR's world headquarters and is being reopened after nearly 11 years of being closed.
NCR still owns the park but it will be operated the group Dayton History. Dayton History's president said his organization has a three year deal to run the park and that hasn't changed.
Leaders hope to eventually connect Old River to Carillon Park, located right across the street.
Molly Blumer, a visitor to the park on Sunday, said it is unfortunate the company is leaving because of the historic ties to Dayton, but is happy the park is back open.
“It means fun, lazy Sunday afternoons,” she said. “My hope is it will become a park people will want to come to each summer regardless if NCR is here or not. It should last forever.”