It's important for your cat to feel safe when using their litter box and so therefore it's important to place the litter box in an area where there are the least amount of people. You also won't want the litter box in your kitchen or near your cat's food. A bathroom is a great place for a litter box or a laundry utility room. You don't want to make your cat feel trapped and it's advisable you don't place it upstairs as this could cause avoidance for smaller or older cats.