An optimization of vapor chamber (VC) region's width and its wick porosity to achieve the minimum temperature rise of the vapor chamber is studied in this paper. The optimization process is carried out by particle swarm optimization (PSO) method. The study is performed at various widths of the vapor chamber, cooling rates, and input powers. The vapor chamber includes two solid copper plates, two wick regions, and vapor region between them. The required chamber characteristics for the optimization process are obtained by solving a complete VC mathematical model, which couples the thermal and hydrodynamic models. The optimum vapor chamber regions' thicknesses and the fluid flow through the vapor chamber regions are studied. The results illustrate that to minimize the chamber temperature, the wick region width must be minimized. They also show that increasing the total width of the chamber from 3 to 7 mm does not have a great impact on the chamber optimized temperature. Moreover, the vapor chamber width does not have a great impact on the optimum wick region width. The optimum width of the vapor region and the chamber walls augments with increasing the total vapor chamber width. Additionally, the form of temperature, streamlines, and velocity distributions at liquid and vapor regions at optimum conditions are not greatly influenced by increasing vapor chamber width.