The processing of short-term memory to long-term memory is done in

"The area of the brain responsible for the consolidation, i.e. processing of short-term memory into long-term memory, is the medial temporal lobe / Hippocampus, parahippocampal gyrus and entorhinal cortex".— Principles of medical physiology "The hippocampus seems to be an important site for the encoding process involved in the consolidation of short-term memory". — RK Marya