What a find!
So much to love. 
Belted 100% cotton lightweight denim chambray blue overalls from the brand DREAMS.
Belt loops are buttoned, side pockets, button flap chest pockets with brand logo, and shoulder pads.
Originally sold at Jordan Marsh, an American department store chain that was headquartered in Boston, Massachusetts and operated throughout New England. 

Size Large
Chest 46" (23" laid flat across)
Inseam 31"
Leg opening width 7 1/2."

Great condition with a few minor blemishes as shown in pictures.