According to the 2011 Census of Bangladesh, Lalmonirhat Sadar Upazila had 79,147 households and a population of 333,166.

Lalmonirhat Sadar had a literacy rate (age 7 and over) of 47.37%, compared to the national average of 51.8%, and a sex ratio of 998 females per 1000 males.

[5][7] As of the 1991 Bangladesh census, Lalmonirhat Sadar has a population of 260876.

[8] Lalmonirhat Sadar Upazila is divided into Lalmonirhat Municipality and nine union parishads: Barobari, Gokunda, Harati, Khuniagachh, Kulaghat, Mogolhat, Mohendranagar, Panchagram, and Rajpur.

They include honors level Lalmonirhat Government College.