Memory devices include an array of memory cells including magnetic tunnel junction regions. The array of memory cells includes access lines extending in a first direction and data lines extending in a second direction transverse to the first direction. A common source includes first linear portions and second linear portions extending at an acute angle to each of the first direction and the second direction. Electronic systems include such a memory device operably coupled to a processor, to which at least one input device and at least one output device is operably coupled. Methods of forming such an array of memory cells including a common source.