U-Store-It 1040 Hortons Ln, Southold, NY11971 U-Store-It in Southold is a self-storage facility. Available storage units start at 5' x 5' and go up to 24' x 12'. The…More rental professionals can help customers choose the right size. U-Store-It also has facilities to store cars, boats, motorcycles, ATVs and jet skis. The rental office sells packing material.