After his rout by McNeil at Whaley's Mill, and the dispersion of his troops at Bragg's school house, Col. Porter kept himself hidden for a few days. He abandoned the idea of raising a militarily significant force, and entered Shelby County on a line of march to the South with fewer than 100 men remaining. He made his way safely through Monroe, Audrain, Callaway and Boone counties, and crossed the Missouri River in a skiff, continuing into Arkansas. Here he organized, from the men who had accompanied him and others whom he found in Arkansas, a regiment of Missouri Confederate cavalry. From Pocahontas, Arkansas, in the latter part of December 1862, as acting brigadier, he moved with his command and the battalions of Cols. Colton Greene and J. Q. A. Burbridge, to cooperate with Gen. John S. Marmaduke in his attack on Springfield. Through a mistake of Gen. Marmaduke, Col. Porter's command did not participate in this attack. It moved on a line far to the east. After the expedition had failed, the commands of Marmaduke and Porter united east of Marshfield, and started to retreat into Arkansas.