The hilly district of Karbi Anglong of Assam faces significant challenges in water supply for domestic and agricultural needs. Rainwater harvesting (RWH) emerges as a critical solution to these water crises. RWH enhances water security, particularly in areas with water scarcity, by reducing reliance on groundwater and surface water sources. Proper identification of suitable sites is essential for constructing RWH systems in watersheds. Suitability classification using geospatial techniques is crucial for this purpose. This research aims to identify and select sites for RWH systems using criteria such as land use/land cover, slope, curve number, contour, and soil type. Remote sensing (RS), geographical information system (GIS), and multi-criteria analysis were employed. GIS, especially valuable in data-scarce regions, is particularly relevant in hilly and remote areas where other data collection methods are challenging. Spatial analysis with GIS software was used to generate thematic layers and integrate them for identifying suitable RWH sites.