The use of Unmanned Aerial Vehicles (UAVs) has grown in almost every field especially the defense and commercial sectors to accomplish a variety of tasks and services. These UAVs form a network called Flying Ad-hoc Network (FANET) and also sometimes referred to as a UAV swarm adhoc network which are different to Mobile Ad-hoc Networks (MANETs) and Vehicular Ad-hoc Networks (VANETs). In this paper, we survey the geographic or position-based routing techniques for FANETs and we also discuss their research gaps. Further, we discuss six prominent routing techniques to get aware of the challenges involved in UAV networks’ quick movement and topological changes. We also present challenges and open research issues for the routing methods involved in FANET.