Price learned that the town of Pilot Knob and one end of the St. Louis and Iron Mountain Railroad was held by Union troops while he was at Fredericktown on September 24. Price did not want to leave a Union force free to operate in his rear, so he decided to move aggressively against the Union column. To accomplish this, he sent Shelby with his division north of Pilot Knob to disrupt the railroad on September 26, while sending Fagan and Marmaduke directly against the Union troops. Ewing commanded the Union force near Pilot Knob, which was 1,456 strong: 856 Union Army soldiers, 450 MSM men, and a group of 150 mobilized civilians. Additionally, Price learned on the 25th that Union Major General Andrew J. Smith and 8,000 men were near St. Louis, which caused him to doubt his ability to take the city.