Memory Arrays Comprising Strings Of Memory Cells 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 directly above a conductor tier. Strings of memory cells comprise channel-material strings that extend through the insulative tiers and the conductive tiers. The channel-material strings directly electrically couple with conductor material of the conductor tier. A through-array-via (TAV) region comprises TAVs that individually extend through the insulative tiers and the conductive tiers into the conductor tier. Individual of the TAVs comprise an upper portion directly above and joined with a lower portion. The individual TAVs comprise at least one external jog surface in a vertical cross-section where the upper and lower portions join. The lower portion is wider in the vertical cross-section than the upper portion where the upper and lower portions join. Other embodiments, including method, are disclosed.