A method used in forming a memory array comprising strings of memory cells comprises forming a stack comprising vertically-alternating first tiers and second tiers. The stack comprises laterally-spaced memory-block regions. Simultaneously, (a), (b), and (c) are formed, where (a): horizontally-elongated trenches into the stack laterally-between immediately-laterally-adjacent of the memory-block regions; (b): channel openings into the stack laterally-between the horizontally-elongated trenches; and (c): through-array-via (TAV) openings into the stack in a stair-step region. Intervening material is formed in the horizontally-elongated trenches, a channel-material string in individual of the channel openings, and conductive material in the TAV openings. Other aspects, including structure independent of method, are disclosed.