It is the Fair Grounds lot where the (fair workers) camp. They open it up to RVers when it's not otherwise in use.

Call them for availability. $15 dry camping, $25 with water and electricity. Dump station available for campers, $10 otherwise. Camp ground host on site was nice and helpful. No other facilities, but it's a great place to stay if you want electricity and water when exploring Jerome and Sedona. Otherwise, I'd go for the free local BLM land down towards Camp Verde.

From their web site:
We have 50 amp and 110 amp service for 35 rigs. We have water to fill up and a dump station. Our rates are $25 for electrical service and $15 to dry camp.

Public dumping - If you are not staying with us, you can dump your rig for $10 or fill your rig with water for $10.