I did not know that about KOA or that the camping was actual in Billing just thought the signs were at the same place. I made the trip a few time but never actually traveled into Billing I was always just looking to get from point A to B, takes a long time to get thru Montana the long direction.That sign is still there. The flagship KOA campground is just south of I-90, along the Yellowstone River. Twenty-Seventh Street, the main drag through downtown Billings, is directly opposite the campground on the north side of the Interstate.
Kampgrounds of America was founded in Billings almost 60 years ago and the corporate HQ has been there ever since. The company has about 600 franchises today. So, KOA is still kind of a big deal in the city.