For strategic planning and decision making on irrigation-related development projects, systematic assessment of irrigable land and the availability of water resources is imperative. This study was initiated with the objective of assessing the surface water resource and irrigable land potential in Amhara region West Gojjam zone, Jabitehnan Woreda using SWAT model and MCDE respectively. For water resource assessment on ungauged catchment using SWAT model, Lah River’s observed flow data were used for sensitivity analysis, model calibration and validation. The result of model performance analysis demonstrated a good agreement between the average monthly simulated and measured values: Nash-Sutcliffe model efficiencies (NSE) of 0.74 for calibration and 0.62 for validation periods. Moreover, the coefficients of determination (R2), 0.83 and 0.82, were obtained during the same period. The calibrated parameter on the gauged catchment was in turn used to estimate runoff yield of the ungauged catchment. The simulated mean monthly and average annual water yields of the Geray and Debolah Watersheds were found to be 0.98m3/s and 0.92m3/s and 11.73m3/s and 11.1m3/s, respectively. To identify potential irrigable land, irrigation suitability factors such as soil type, slope, land cover/use, and river proximity were taken into account. The surface irrigation land suitability analysis indicate that 90.75% of soil , 95.6 % of land cover/use and 95.15 % slope in the study area are in the range of highly suitable to marginal suitable for surface irrigation system. The weighted overlay analysis of these factors gave potential irrigable land among river catchments as Birr and Tikur wuha (7,831.09ha), Gunagun and Leza (17,658.08ha), Lah, Geray, Arara, Debolah, Guysa and Silala (20,105.98ha). Three crops such as onion, cabbage and tomato were selected to grow on the identified irrigable areas, and their gross irrigation demand was calculated by using nearby climatic stations. By comparing gross irrigation demand of irrigable land with available flow in rivers, the actual surface irrigation potential of the study area was obtained as 4,499.7ha. In conclusion, the SWAT model can be used to analyze ungauged watershed runoff yield in areas that have similar hydrometeorological characteristics as those of the Lah Watershed in the region and water should be stored in rainy seasons to irrigate all the irrigable land potential.