On starting out, St Leger, who knew that a surprise might be attempted, outlined his order of march with great care.  A detachment from one of the battalions was sent on ahead, and this was later joined by Captain Brant with a party of his warriors.  Five columns of Indians went in front, in single file; the flanks also were protected by Indians at a distance of one hundred paces from the central column.

It was intended that the first blow should be struck at Fort Stanwix, on the head-waters of the Mohawk.  This was an old English stronghold that had fallen into decay, but was being repaired and defended in the interest of the revolting colonies by Colonel Peter Gansevoort.  It lay on the traffic-road to Oneida Lake, and was considered a strong point of vantage.  Its garrison was made up of about seven hundred and fifty colonials.  They had provisions enough to last for six weeks and a goodly supply of ammunition, and hoped to be able to withstand attack until help should arrive.

The English leader reached this fort on August 3, and immediately began to invest it.  A demand was sent in under a flag of truce calling upon the garrison to surrender.  St Leger said it was his desire ’to spare when possible’ and only ‘to strike where necessary.’  He was willing to buy their stock of provisions and grant security to all within the fort.  The offer was generous, but the garrison rejected it with a good-tempered disdain and the siege went on with renewed earnestness.  The Indians, hiding in the thickets, poured their fire upon those who were working on the walls.  The presence of the savages lent a weird fury to the scene, made it, indeed, well-nigh uncanny.  One evening in particular they ’spread themselves through the woods, completely encircling the Fort, and commenced a terrible yelling, which was continued at intervals the greater part of the night.’  Fort Stanwix was soon in dire straits.  The news of the investment had sent a thrill through the whole of the Mohawk valley.  The colonials came together in haste, and soon about a thousand of them, led by Nicholas Herkimer, were ascending the river in straggling array.  They hurried on their course with such zeal that they did not even send out scouting parties to warn them of danger and prevent surprise.  On August 5 this relief force was close to Oriskany, and only eight miles distant from St Leger’s position.  Herkimer now matured a clever plan, the success of which he confidently expected would bring him victory.  He chose three men and sent them forward to gain entrance to the fort and to tell Gansevoort that help was coming.  The moment they arrived the besieged were to fire three guns in rapid succession.  This was to be Herkimer’s signal; he would speed at once along the road to the British position and fling himself on its rear, while, at the same time, Gansevoort must issue forth and attack it in front.  St Leger’s army, it was hoped, would crumble in hopeless defeat between two shattering fires.