The electronically coupled distributed generations play a crucial role in operating islanded microgrids. The improper locations and inappropriate droop coefficients of droop-controlled distributed generations in islanded microgrids lead the system frequency and node voltages to go beyond the acceptable ranges. The operation of an islanded microgrid by droop-controlled distributed generations with their fixed droop coefficients at different load models causes different variations of the system frequency and node voltages. It also causes different power losses at different load models. Thus, the optimal droop coefficients of the distributed generations at their existing locations, as well as both the optimal locations and droop coefficients of the distributed generations, are obtained for different load models separately by chaotic particle swarm optimization technique based on minimization of the system frequency deviation, deviation of the reference node voltage (as the reference node voltage has a significant impact on other node voltages) and power losses of the network, aiming to choose the suitable option for effective and efficient operation of an islanded microgrid at any load model. The effectiveness of the methodology is tested on a 33-node radial islanded microgrid.