Grocery, liquor, and more! Riverside Red X is the store to explore, where you'll find something new and interesting at every turn. A landmark in Kansas City for 70 years, Riverside Red-X is the most unique 90,000 sq. ft. super convenient discount store in the metro Kansas City area. And museum, too. Established in 1948. Red X was founded by E.H. Young in October of 1948. Red X began as a small filling station and grew to the store it is today.