Belvidere "MID-NIGHT" Flea Market June 20, 2026. 3pm to Midnight Boone County Fairgrounds! BELVLIDERE, ILLINOIS. It’s MOON-LITE Madness, on Saturday June 20, 2026 from 3PM TO MIDNIGHT AT THE Boone County Fairgrounds located at 8791, IL. Rt. 76 in Belvidere, Illinois Flea Market - Antiques, Collectibles, Furniture, Estate Jewelry and more! Late night flea market […]