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

🇺🇸 N77535 - Boeing 737NG 824/W - United Airlines UAL2360/UA2360, Laguardia (LGA) to Chicago O'Hare (ORD) - 4.3 mi away @ 36400 ft, heading SW at 397 mph. Spotted 21x before. [09:04:15 PM CST] #AA7E79 #N77535 #B738 #UNITED #UAL2360 #UA2360 #ADSB #ADSBbot