Sonargaon and Homna upazilas on the north, Matlab upazila on the south, Daudkandi upazila on the east, Munshiganj Sadar and Sonargaon upazilas and the meghna river on the west.

Gazaria thana was established in 1954 and was turned into an upazila in 1983. It consists of 8 union parishads, 114 mouzas and 120 villages.

Gazaria Upazila is located in Munshiganj District. Upazilla(s)/Thana(s) in Munshiganj are Gazaria Upazila, Lohajang Upazila, Munshiganj Sadar Upazila, Serajdikhan Upazila, Sreenagar Upazila, Tongibari Upazila.