I was told that Shenandoah will perform at 7 pm on Sunday at the Fairgrounds. Is this correct? If so, I assume it has nothing to do with the Fair since it will be closed. Will there be ticket sales/how much?

Yes on the square. You can go to the website to get time frames.

There was a miss print Shenandoah will be performing on the square in the old downtown district in Springfield, you can go to the city's website for more details

On the square I think