An inkjet printhead includes: an elongate support having a printhead mounting surface; a plurality of butting printhead chips mounted on the printhead mounting surface, each printhead chip having an ink ejection surface including one or more nozzle rows; and a grout material disposed between butting edges of each butting pair of printhead chips. Each printhead chip has a grouting trench defined in the ink ejection surface, the grouting trench extending alongside at least one butting edge and the grouting trench being disposed between an endmost nozzle of each nozzle row and the butting edge.