Irrigation is an all-around critical factor that is required to guarantee food security and agricultural development. Water for irrigation is derived from three sources: rainfall, groundwater water, and river water. Groundwater and rainwater are both influenced by geographical features, whereas river water is linked to the river systems of both neighboring and distant nations. The government of Bangladesh took a project on the Teesta River point in Dalia, Lalmonirhat district, to construct the Teesta Barrage Irrigation Project (TBIP) via a canal that supplied farmers with irrigation water. This irrigation initiative encompasses three districts in Bangladesh’s northern region. The present article endeavors to investigate comprehensively the effects of the Teesta barrage irrigation project on the agricultural output of the inhabitants residing in the Nilphamari district of Bangladesh. The results indicate that the irrigation project has contributed to a rise in agricultural output and an improvement in the financial standing of the producers residing in the study area. Nevertheless, while this research is founded upon both qualitative and quantitative methodologies, the quantitative approach predominates in its justification. The social survey, an interview schedule, and observation were all used during the course of this investigation. This chapter revealed that crop production underwent a number of enhancements, including modifications to cash crop patterns, income levels, and output quantities; crop varieties were also altered, cultivation periods were extended, and cultivation and harvesting techniques were modified. This study also found that the TBIP primarily benefits producers from the upper and middle classes. Conversely, the marginal level of cultivators does not receive the anticipated and adequate benefits from TBIP, and their circumstances remain unchanged.