Yavapai County Jeep Posse Press Release Saturday May 1, 2019 7:20 am. For immediate release. Yavapai County Jeep Posse (YCJP) volunteers have been instrumental in supporting Yavapai County Sheriff’s Office (YCSO) with fire evacuations and road blocks since its inception in 1952. Jeep Posse efforts are in coordination with other search and rescue units, from…