Apparatuses and methods for memory array accessibility can include an apparatus with an array of memory cells. The array can include a first portion accessible by a controller of the array and inaccessible to devices external to the apparatus. The array can include a second portion accessible to the devices external to the apparatus. The array can include a number of registers that store row address that indicate which portion of the array is the first portion. The apparatus can include the controller configured to access the number of registers to allow access to the second portion by the devices external to the apparatus based on the stored row addresses.