The Scotland midfielder has admitted in the past considering his future at Old Trafford.
But he now tells manutd.com: "There's nowhere else I want to be. I have no aspirations to play anywhere else - in this country or abroad. I'm already at the biggest and best club in the world. Anywhere after this would be a step down.
"You don't know what the future holds - you can never say never - but as long as I'm happy and playing regularly at United, there's nowhere else I'd rather be. I've been here since I was 15 and I want to continue at United and be part of this club's success for years to come."