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

🇺🇸 N776YX - EMBRAER S A ERJ 170-200 LR - Republic Airlines RPA3527/YX3527, Chicago O'Hare (ORD) to Northwest Arkansas Ntl (XNA) - 3.8 mi away @ 30250 ft, heading SW at 442 mph. Spotted for first time! [08:47:27 PM CDT] #AA818D #N776YX #E170 #BRICKYARD #RPA3527 #YX3527 #autopilot #ADSB #ADSBbot