Groundwater is a strategic resource for irrigated agriculture particularly in arid regions. Management of groundwater resources is essential to preserve sustainability while conserving economic interests. In this research, crops areas and water depletion by wells in an agricultural plain are optimized. This done by a novel hydro-agronomic-based simulation-optimization approach in which SWAT as the agronomic and MODFLOW as the groundwater simulation models are coupled with the Particle Swarm Optimization (PSO) algorithm. Maximization of the net benefit gained from crops production is defined as the objective function. The decision variables are cultivation area for four major irrigated crops and irrigation depths (groundwater withdrawals). Groundwater depletion for irrigation is limited to a pre-defined value as the stability level. The PSO-SWAT-MODFLOW model is applied for Asemanabad plain in west of Iran. Results show that by optimum crops area and irrigation planning the agricultural net benefit is increased significantly comparing the present situation existing in the plain while the aquifer's depletion remains in the stable range. By sensitivity analyses, it is found that the crops' price has a major effect on the optimum cropping pattern and water consumption while improvement of the irrigation efficiency has a negligible impact on the plain's optimum agricultural net benefit. (C) 2020 Elsevier Ltd. All rights reserved.