"If I could thank you all individually, I would. There are so many of you.
"You've been incredible - not just these past few weeks, but the past few years.
"You've always been there to support me. I can't thank you enough."
Ennis was asked to unveil a golden version of the plaque commemorating her achievements which is already outside Sheffield's Town Hall.
Council leader Julie Dore said: "You have truly helped to change this great city of ours from a city of steel to a city of gold. Sheffield is your home and we know you are so proud of the city - maybe as much as we are of you."