Looking to get outside? Arnold, Missouri is situated between the Meramec and Mississippi Rivers and is surrounded by parks. Walk the Arnold City Park Trail or venture to one of the nearby county parks like Cliff Cave County Park or the Mastodon State Historic Site. At just 20 miles from downtown St. Louis, it’s easy to hop into the city for business meetings or sightseeing. At the end of the day, just head down to Arnold to get away from it all.