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

🇺🇸 N77578 - Boeing 737MAX 9 - United Airlines UAL1678/UA1678, San Francisco (SFO) to Ronald Reagan Washington Ntl (DCA) - 7.3 mi away @ 38950 ft, heading E at 556 mph. Spotted 2x before! [01:57:23 PM CDT] #AA7F08 #N77578 #B39M #UNITED #UAL1678 #UA1678 #ADSB #ADSBbot