Original: Upper Egypt (Sa'id Misr) is the strip of land, on both sides of the Nile valley, that extends from the cataract boundaries of modern-day Aswan north to the area between El-Ayait and Zawyet Dahshur (which is south of modern-day Cairo).
Simplified: Upper Egypt is a narrow strip of land on both sides of the Nile that extends from modern-day Aswan to the area south of modern-day Cairo.