Yes, you can freeze:
From Super Baby Food:
Mashed potatoes will keep well-wrapped in the freezer for up to 10 months. Freeze whole baked potatoes for up to 3 months; thaw in refrigerator overnight, wrap in foil and bake at 350 for 30 min. Bake frozen unthawed whole potatoes at 350 for 45 min. Remove foil for last 10 min of baking.
HTH