The present study examined the diversity of Bacillariophyceae members from four different biotopes in the Meerut and Hastinapur regions of western Uttar Pradesh, India. Since there are no previous records of diatom diversity from Meerut and Hastinapur, this study serves as the first documentation of the diatom flora in these areas. Our investigation reported 33 taxa of diatoms belonging to 6 orders, 9 families, and 12 genera, including: Achnanthidium exiguum, A. subatomus, Craticula ambigua, C. cuspidata, Frustulia rhomboides var. crassinervia, Navicula capitatoradiata, N. cryptotenella, N. notha, N. pupula, N. zanonii, Trachyneis aspera, Pinnularia dariana, P. subcapita, P. viridis, Ctenophora pulchella, Fragilaria capucina, F. capucina var. rumpens, F. intermedia, Nitzschia reversa, N. acicularis, N. baculum, N. capitellata, N. filiformis, N. fruticosa, N. linearis, N. palea, N. constricta, Tryblionella hungarica, Gomphonema abbreviatum, G. constrictum, G. truncatum, and Tabellaria japonica. Additionally, wetlands and drains near the Ganga River in Hastinapur were found to host the highest number of species, while the lowest diversity was observed in samples collected from an anthropogenic pond at Chaudhary Charan Singh University, Meerut (U.P.), India.