This document analyzes the performance of the Zone Routing Protocol (ZRP) in mobile ad hoc networks using the OPNET simulator. It provides an overview of ZRP, including that it is a hybrid routing protocol that uses a proactive approach within routing zones and a reactive approach between zones. The document describes simulating ZRP with 20, 40, and 60 nodes and measuring its throughput, load, data dropped, and delay. The results showed that as node count increased, ZRP's throughput, load, and data dropped increased, while delay also rose with more nodes. ZRP thus performed best with fewer nodes and worse with more nodes in the simulated mobile ad hoc networks.