A method of forming a memory array, comprising: forming a substrate to comprise a plurality of spaced apart lines of first electrode material, and to comprise trenches directly over the spaced apart lines and in one-to-one correspondence with the spaced apart lines; the trenches and the lines of first electrode material extending along a first horizontal direction; forming access device materials within the trenches to partially fill the trenches and thereby narrow the trenches, the access device materials including an electrically conductive metal-containing material and at least two insulative materials, the insulative materials being between the electrically conductive metal-containing material and the first electrode material; forming memory element material within the narrowed trenches, the memory element material forming a plug that extends into the access device materials, and the access device materials extending along a bottom and two sides of the memory element plug, the memory element material being configured as a plurality of spaced apart lines in one-to-one correspondence with the trenches; forming second electrode material over the memory element material lines and over regions between the spaced apart memory element lines; forming a patterned mask over the second electrode material, the patterned mask comprising a plurality of spaced apart lines, the spaced apart lines of the patterned mask extending along a second horizontal direction that is orthogonal to the first horizontal direction of the lines of first electrode material; and transferring a pattern from the patterned mask through the second electrode material, through the memory element material and through the access device materials to thereby pattern the access device materials and memory element material into array of memory cells, and to pattern the second electrode material into top electrode lines extending over the memory cells and orthogonally to the lines of first electrode material. forming a substrate to comprise a plurality of spaced apart lines of first electrode material, and to comprise trenches directly over the spaced apart lines and in one-to-one correspondence with the spaced apart lines; the trenches and the lines of first electrode material extending along a first horizontal direction; forming access device materials within the trenches to partially fill the trenches and thereby narrow the trenches, the access device materials including an electrically conductive metal-containing material and at least two insulative materials, the insulative materials being between the electrically conductive metal-containing material and the first electrode material; forming memory element material within the narrowed trenches, the memory element material forming a plug that extends into the access device materials, and the access device materials extending along a bottom and two sides of the memory element plug, the memory element material being configured as a plurality of spaced apart lines in one-to-one correspondence with the trenches; forming second electrode material over the memory element material lines and over regions between the spaced apart memory element lines; forming a patterned mask over the second electrode material, the patterned mask comprising a plurality of spaced apart lines, the spaced apart lines of the patterned mask extending along a second horizontal direction that is orthogonal to the first horizontal direction of the lines of first electrode material; and transferring a pattern from the patterned mask through the second electrode material, through the memory element material and through the access device materials to thereby pattern the access device materials and memory element material into array of memory cells, and to pattern the second electrode material into top electrode lines extending over the memory cells and orthogonally to the lines of first electrode material.