Path Loss (PL) models are an essential factor affecting the network design and its operation. With different environmental conditions, interpreting the PL characteristics in an open environment is a complex problem. In this work, the propagation of LoRa technology in a campus is investigated in order to propose an accurate PL model. The measurements are taken place in two outdoor regions of the Electrical Engineering Technical College in Baghdad, Iraq. Measured field data correlates with global propagation models, demonstrating that ERICSON model results after an evaluation are likely to produce positive results. Different environment conditions make the global PL models difficult to generalize, yield some errors between the measured and estimated PL. For addressing this downside, Particle Swarm Optimization (PSO) has been based to develop the model parameters, hence matching the model to reality. The ERICSON model’s parameters have been improved to the best fit with measured data, and the lowest Root Mean Square Error (RMSE) is gained equals to 3.7168dB and 5.4030dB for the two adopted regions.