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

🇺🇸 N38451 - Boeing 737NG 924ER/W - United Airlines UAL1970/UA1970 (SLC-IAD-ORD) - 4.0 mi away @ 31000 ft, heading ESE at 473 mph. Spotted 6x before! [11:56:55 AM CDT] #A46D47 #N38451 #B739 #UNITED #UAL1970 #UA1970 #ADSB #ADSBbot