"It's a day of turning to something positive," Cary Mayor Harold Weinbrecht said. "It's a day of something special for Nancy, through this beautiful bench and this wonderful location."
Cooper vanished in July, her body was found in an unfinished neighborhood, not far from her home.
Now, the bench and its location provide a bittersweet link to the Cary mother who spent many happy times nearby.
"My sister found solace in exercise, especially on these trails," Cooper's sister, Jill Dean said. "This moment has moved me, and I hope that when you enjoy this bench with your community, you will share a moment in the memory of my sister."
"I want all of you to go home, and hug those that you love. Keep them close! And while all the thanks have been said, there are just no words left," Cooper's mother Donna Rentz said.
Cary Police have not named a person of interest in the case, though their investigation has focused on Cooper's husband Brad.
Police say what he told officers about his wife's disappearance and what he said in a videotaped disposition released Friday have not been consistent.