Land-use practices have a significant impact on the environment, sustainability, and human well-being. The main objective of this research was to characterize and describe the effects of land-use change on vegetation structure and composition along the Rongai River. To identify the numerous plant types at diverse land uses along the Rongai River, a reconnaissance study was initially conducted. The descriptive survey design was also used for the study, respondents were administered with structured questionnaires (closedended) to assess the land-use system with the major threat to the sustainability of River Rongai. The Shannon Diversity Index and species dominance in the vegetative communities were all calculated. Based on nearby land uses, three riverside sampling sites were selected for this study. Three transects, each 100 meters long and running parallel to the river, were set up at each point. Randomly, all trees with a Diameter at Breast Height (DBH≥2 cm) about 1.4 m above the ground were identified. Three major land-use types identified in the study areas were forests, agricultural and grazing areas. Tree species that were most dominant includes: Vachellia xanthophlea, Syzygium cordatum, Vachellia abyssinica, Erythrina abyssinica, Eucalyptus salgina and Ficus natalensis. ANOVA showed that land uses, plant vegetations and the interaction effect of site and plant vegetation have no significant (P≥0.05) effect on length.