Memory arrays and methods used in forming a memory array comprising strings of memory cells

A memory array comprising strings of memory cells comprises laterally-spaced memory blocks individually comprising a vertical stack comprising alternating insulative tiers and conductive tiers. Operative channel-material strings of memory cells extend through the insulative tiers and the conductive tiers. Insulative pillars are laterally-between and longitudinally-spaced-along immediately-laterally-adjacent of the memory blocks. The pillars are directly against conducting material of conductive lines in the conductive tiers. Other arrays, and methods, are disclosed.