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

🇺🇸 N87531 - Boeing 737NG 824/W - United Airlines UAL755/UA755 (PHX-IAD-BOS) - 4.2 mi away @ 37300 ft, heading E at 670 mph. Spotted 7x before! [06:24:06 PM CST] #AC0BC4 #N87531 #B738 #UNITED #UAL755 #UA755 #ADSB #ADSBbot