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

🇺🇸 N14735 - Boeing 737NG 724/W - United Airlines UAL590K/UA590K (BWI-ORD-DFW) - 4.8 mi away @ 40000 ft, heading SW at 515 mph. Spotted 21x before! [09:03:48 PM CDT] #A0BF90 #N14735 #B737 #UNITED #UAL590K #UA590K #ADSB #ADSBbot