The ghost town of Kirwin, Wyoming is approximately 34 miles southwest of Meeteetse, Wyoming. It is recommended you use a 4WD vehicle as you have to ford the Wood River twice with the last several miles being rocky jeep trail.
In the early 1900s it had a population of about 200 people who mined gold and silver, but an avalanche in 1907 destroyed several buildings and killed three people, so the town was abandoned later that spring. The US Forest Service has preserved many of the buildings in Kirwin, including informational/historical placards.
If I remember correctly, there are three "campsites" -- meaning three bear boxes. You are just outside of Yellowstone National Park, and grizzly and black bears frequent the area. Last I knew there is also a wolf pact in the area. The campsites are on unlevel and slanted ground, so it's best to camp on the gravel bars. While there is a vault toilet on site, there is no potable water. This is a very remote site at an elevation of 9,200 feet. But if you can make it there, it is well worth the trip.