In mobile ad hoc networks, along with the increased network size, the clustering scheme becomes more important technique to efficiently manage the network and utilize the network resources for the hierarchical routings based on the clustering scheme. Therefore, we have proposed the autonomous clustering for mobile ad hoc networks. The main feature of the autonomous clustering is that each cluster maintains a multihop cluster structure. This paper shows the effectiveness of the autonomous clustering by investigating that the autonomous clustering and 1-hop clustering have an influence on the hierarchical routings.