General Josiah Harmar had noticed the large number of flatboats descending the Ohio and ordered the officer of the day to take an account of the number of boats that passed the garrison. From the tenth of October 1786, until the 12th of May 1787, 127 boats, 2,689 souls, 1,333 horses, 756 cattle and 102 wagons passed Muskingum bound for Limestone (Maysville, Ky.), and the Rapids (Louisville, Ky.). An average of 3000 flatboats descended the Ohio River every year between 1810 and 1820. At Limestone the boats became so numerous that they frequently were set adrift in order to make room for others. General Harmar noted that he had purchased at Limestone from 40 to 50 flatboats at the moderate price of from $1 to $2 each, to be used in the construction of Fort Washington at Cincinnati.
From Ken Downing's Mason County Blog