Being unable to obtain any supplies at Wilmington, Lord Cornwallis determined to march on into Virginia and to effect a junction with the British force under General Arnold operating there. Arnold advanced to Petersburg and Cornwallis effected a junction with him on May 20. The Marquis de la Fayette, who commanded the colonial forces here, fell back. Just at this time the Count de Grasse, with a large French fleet, arrived off the coast, and, after some consultation with General Washington, determined that the French fleet and the whole American army should operate together to crush the forces under Lord Cornwallis.  
The English were hoodwinked by reports that the French fleet was intended to operate against New York, and it was not until they learned that the Count de Grasse had arrived with twenty-eight ships of the line at the mouth of the Chesapeake Bay that the true object of the expedition was seen. A portion of the English fleet encountered them, but after irregular actions, lasting over five days, the English drew off and retired to New York. The commander-in-chief then attempted to effect a diversion, in order to draw off some of the enemy who were surrounding Cornwallis. The fort of New London was stormed after some desperate fighting, and great quantities of ammunition and stores and fifty pieces of cannon taken. General Washington did not allow his attention to be distracted. Matters were in a most critical condition, for although to the English the prospect of ultimate success appeared slight indeed, the Americans were in a desperate condition. Their immense and long-continued efforts had been unattended with any material success. It was true that the British troops held no more ground now than they did at the end of the first year of the war, but no efforts of the colonists had succeeded in wresting that ground from them. The people were exhausted and utterly disheartened. Business of all sorts was at a standstill. Money had ceased to circulate, and the credit of Congress stood so low that its bonds had ceased to have any value whatever. The soldiers were unpaid, ill fed, and mutinous. If on the English side it seemed that the task of conquering was beyond them, the Americans were ready to abandon the defense from sheer exhaustion. It was then of paramount necessity to General Washington that a great and striking success should be obtained to animate the spirits of the people.
 
Cornwallis, seeing the formidable combination which the French and Americans were making to crush him, sent message after message to New York to ask for aid from the commander-in-chief, and received assurances from him that he would at once sail with 4000 troops to join him. Accordingly, in obedience to his orders, Lord Cornwallis fortified himself at Yorktown.
 
On September 28 the combined army of French and Americans, consisting of 7000 of the former and 12,000 of the latter, appeared before Yorktown and the post at Gloucester. Lord Cornwallis had 5960 men, but so great had been the effects of the deadly climate in the autumn months that only 4017 men were reported as fit for duty.
 
The enemy at once invested the town and opened their trenches against it. From their fleet they had drawn an abundance of heavy artillery, and on October 9 their batteries opened a tremendous fire upon the works. Each day they pushed their trenches closer, and the British force was too weak, in comparison with the number of its assailants, to venture upon sorties. The fire from the works was completely overpowered by that of the enemy, and the ammunition was nearly exhausted. Day after day passed and still the promised re-enforcements did not arrive. Lord Cornwallis was told positively that the fleet would set sail on October 8, but it came not, nor did it leave port until the 19th, the day on which Lord Cornwallis surrendered.
 
On the 16th, finding that he must either surrender or break through, he determined to cross the river and fall on the French rear with his whole force and then turn northward and force his way through Maryland, Pennsylvania, and the Jerseys. In the night the light infantry, the greater part of the guards, and part of the Twenty-third were embarked in boats and crossed to the Gloucester side of the ............