Padma River
Zajira Upazila has a total area of . About two-thirds is land and one-third is water, chiefly the Padma River, which flows through the northern part of the upazila. It borders Munshiganj District to the north, Naria Upazila to the east and south, Shariatpur Sadar Upazila to the south, and Madaripur District to the west.