[5] The Port of Jugdia (presently in Sirajpur Union) gained relevance as an important commercial seaport during the Bengal Sultanate period.

In 1853, the British East India Company set up a factory in Jugdia and a textile mill there in 1857.

During the Bangladesh Liberation War of 1971, a Razakar force was established in Companiganj by the grandsons of Moulvi Minnat Ali of Bamni.

[5] A brawl took place near the sluice gate on Banchharam Road between the Bengali freedom fighters against the Pakistan Army and their collaborators on 4 September.

A number of other encounters took place in Companiganj, with the Liberation of Bamni leading to the death of seven freedom fighters including Sadar BLF Commander Ohidur Rahman Wadud.

On 2 July 1983, Companiganj Thana was upgraded to an upazila (sub-district) as part of President Hussain Muhammad Ershad's decentralisation programme.

At the 2022 Bangladeshi census, the upazila had a population of 301,310, with a sex ratio of 874.7 males for 1000 females.

Companiganj had a literacy rate (age 7 and over) of 51.31%, compared to the national average of 51.8%, and a sex ratio of 1087 females per 1000 males.

English medium - Oxford school and College (2017) Cultural organisations Club 22, Press Club, Companigonj, three public libraries, one cinema hall and twenty-six playgrounds There are 242 mosques in Companiganj with notable ones including the historic Eidagazi Mosque in Charhazari as well as the Budi Mosque in Basurhat.