A reinforced paperboard box for storage and shipping of elongated items is described. The box is formed from a single piece of paperboard and may be rapidly assembled without the use of tools. The box comprises an elongated rectangular bottom panel, first and second joined side panels, a top panel, a front reinforcing panel and dividing partition all foldably joined at elongated edges and constructed to form a multi-level elongated box. The first side panel has a pair of abutting end panels foldably joined to either end, with a tab receiving panel and a locking panel foldably joined to either side of the end panel. The second side panel has a pair of end panels foldably joined to either end, that are locked in place by the locking panels and tab receiving panels of the first side panel. The dividing partition includes at least two pair of cuts and a series of perforations enabling the dividing partition to be folded inwardly so as to divide the interior space of the box into at least two compartments while providing additional strength and resistance to bending and crushing forces. Variations of the invention include an additional strengthening panel foldably joined to the dividing partition. Other variations include a provision for a half-width partition and various cuts and perforations to provide for specially shaped compartments for accessories such as golf balls and videocassettes. Further variations provide for structural cells and for container shortening panels and positioning panels at the container ends.