Forest ecosystems in the lower Garhwal Himalayas are severely threatened by urbanization, commercial activities, and resource overuse, leading to fragmented and degraded habitats. Given these threats, modern biodiversity assessments are crucial for conserving the remaining forest patches in the Himalayan ecosystem. The urbanization of natural and semi-natural habitats is a primary driver of habitat loss and fragmentation, reducing both the quantity and quality of habitats, which negatively impacts biodiversity. The lower western Himalayas, strongholds of biodiversity, face rapid deforestation and habitat degradation due to anthropogenic activities. Butterflies, due to their sensitivity to environmental changes, serve as effective indicators of the ecological impacts of urbanization and landscape development. In this study, butterfly diversity was monitored across different land use types in the lower Garhwal Himalayan region, focusing on natural forests and urban landscapes. The data collection spanned two years (2022–2024), using seasonal sampling surveys across 288 transects. A total of 34,849 individuals, representing 129 species, were recorded. Of these, 113 species were identified in natural forest habitats, while 83 species were observed in urban areas. The data analysis was conducted using Past software (version 5.0.2), revealing significantly higher species richness and butterfly abundance in the natural forest sites compared to urban areas. These results highlight significant differences in butterfly species' richness and abundance, reflecting the impact of land use changes in the valley. These findings underscore the value of butterflies as bioindicators of land use alterations and can inform land use planning and conservation strategies in the region, promoting areas for future biodiversity preservation.