At Yorktown in 1781, the combined American and French armies of 15,000 penned in a British army of what size?

1. The French fleet gained control of American coastal waters and ferried the allied troops down Chesapeake Bay. 2. The combined armies of Washington and Rochambeau totaled 15,000 men. 3. They penned in an army of 8,000 under Lord Cornwallis at Yorktown, who surrendered on October 19, 1781. 4. Rochambeau's 6,000 was the French expeditionary force, one part of the besieging side, not the besieged. _Source: "An Outline of American History" (USIA, 1990, public domain), Ch 2 "The War of Independence"_