A letter from General Elijah Wadsworth to Governor Return Jonathan Meigs:
Canfield 20th April 1813The flank companies in 18th and 19th century warfare were the two companies in each infantry battalion that took the right and left positions in a line of battle. Traditionally, the right company was a position of honor given to grenadiers, and the left flank likewise was given to the light infantry. The battalion would march from the right by flank or in column, so that the right company was "on point": the left company would either form the rear guard or detach itself to serve as scouts and flankers.
By express, have just recd. Your letter of the 17th. Inst. directing a flank Company to be detached & march to lower Sandusky.
Sir to compleat this Object I will immediately order Capn. McArther Commanding one of the flank Companies, to march with his company to lower Sandusky.
Respectfully Your Obedt. Servt.
In the Canadian as well as American militia, flank companies were similar to minute-men, picked groups of younger and more active citizens who were better equipped and prepared for militia service on a short notice. General Wadsworth's deployment of Captain McArthur's company was an emergency measure, since in April 1813 the last of the 6-month militia brigades from Pennsylvania and Virginia were dismissed from the Northwest Army, leaving General Harrison with less than 800 men to guard the frontier.
Elijah Wadsworth was the Ohio Militia Major General in charge of the 4th Division, which basically consisted of all of the Ohio militia in the northeastern portion of the state. It was 1300 men from Brigadier General Simon Perkins' brigade of this division who marched to Lower Sandusky and built a small stockade that would be called Fort Stephenson. McArthur's Company was called out to garrison this post.