A method used in forming a memory array comprising strings of memory cells comprises forming memory blocks individually comprising a vertical stack comprising alternating insulative tiers and conductive tiers. Channel-material strings extend through the insulative tiers and the conductive tiers. Horizontally-elongated trenches are between immediately-laterally-adjacent of the memory blocks. Conductor material is in and extends elevationally along sidewalls of the trenches laterally-over the conductive tiers and the insulative tiers and directly electrically couples together conducting material of individual of the conductive tiers. The conductor material is exposed to oxidizing conditions to form an insulative oxide laterally-through the conductor material laterally-over individual of the insulative tiers to separate the conducting material of the individual conductive tiers from being directly electrically coupled together by the conductor material. Additional embodiments are disclosed.