Map of the St. Louis area showing the position and track of the aircraft described in the post.

🇺🇸 N888KG - Bombardier Challenger 300 - N888KG LLC N888KG - 3.5 mi away @ 20600 ft, heading WNW at 413 mph. Spotted for first time! [03:24:26 PM CDT] #AC3C75 #N888KG #CL30 #N888KG #ADSB #ADSBbot