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 carpet, balcony, air conditioning, furnished, hardwood floor, walk-in closets, on-site laundry, and dishwasher. It has building amenities including on-site laundry, storage, garage parking, controlled access, package service, elevator, swimming pool, outdoor space, business center, fitness center, and residents lounge. Cats and dogs are allowed, making it a pet-friendly building.