Mansion House Apartments 300 N 4th St, St. Louis, MO is a rental apartment building with 8 floorplans available. It is located in the Downtown St. Louis neighborhood of St. Louis. It has apartment amenities including walk-in closets, furnished, carpet, hardwood floor, air conditioning, balcony, on-site laundry, and dishwasher. It has building amenities including controlled access, residents lounge, package service, garage parking, outdoor space, fitness center, storage, business center, elevator, swimming pool, and on-site laundry. Cats and dogs are allowed, making it a pet-friendly building.