Preheat oven to 325°.
Place ham on a broiler pan lined with foil. Insert meat thermometer into thickest portion of pork. Bake at 325° for 1 hour. Score outside of ham in a diamond pattern. Combine cranberry sauce, sugar, and mustard; brush over ham. Bake an additional 35 minutes or until thermometer registers 140°. Transfer ham to a platter; let stand 10 minutes before slicing.