1. A system for automatic geofence determination, comprising: an interface configured to receive a plurality of data samples collected during one or more trips; and a processor configured to: determine a set of nodes for the one or more trips, wherein members of the set of nodes are those data samples of the plurality of data samples sharing a characteristic; determine a cluster, wherein members of the cluster are nodes within a threshold distance of each other; determine a geofence, wherein a location and a size of the geofence is defined based on a location and a size of the cluster; and output the determined geofence for display on a display device.