Sullivan’s Soldiers Discover The Genesee Valley

Today, we call it the Genesee Valley. To Sullivan’s soldiers, the broad plain surrounding the great Seneca town of Chenussio was the Genesee Flatts, a beautiful vista that remained etched in memory long after the campaign ended. Soon, very soon, to American pioneers scanning maps of the western frontier, the entire region would come to be known simply as the Genesee Country.

Before that, however, there was the Sullivan Expedition. It entered the Genesee Valley as a military campaign. It left behind something far more enduring. More than 4,000 soldiers carried home eyewitness accounts of a fertile country few Americans had ever seen.

Shortly after noon on Tuesday, September 14^th, 1779, Lieutenant Erkuries Beatty and his fellow soldiers had finished destroying a “great abundance” of corn and beans.¹ He—and the men with him—were about to behold a sight unlike anything they had seen before. For a nineteen-year-old lieutenant who had already witnessed Brandywine, Germantown, Valley Forge, Monmouth, and the Onondaga campaign, that was saying something.

As a fifteen-year-old privateer, Beatty captured a British transport in 1775. A year later, he enlisted in the Continental Army.² The private became an Ensign when he was assigned to the 4^th Pennsylvania Regiment. While the now Lieutenant Beatty escaped the Battle of Brandywine unscathed, he was badly wounded at Germantown. That didn’t stop him from spending the winter with George Washington at Valley Forge. After Monmouth, he joined Colonel Van Schaick’s expedition against the Onondagas before finally accompanying General Clinton to meet with the Sullivan campaign down the Susquehanna River.³

As Sullivan’s army advanced into the interior of Western New York, its officers repeatedly recorded the remarkable agricultural landscape before them. Their journals described “most excellent meadows,”⁴ “large cornfields,”⁵ “fine orchards,”⁶ “compact and neatly built”⁷ towns, and some of the “richest soil”⁸ they had observed.

What awaited them beyond the marsh dwarfed everything they had seen thus far. Before crossing the Genesee River, they “came upon a very beautiful flat of great extent growing up with wild Grass higher in some places than our heads.”⁹

Before their eyes lay the Genesee Flats, that expansive, fertile flatland where the Genesee Valley is at its widest. Again and again, their journals returned to the same themes—beauty, abundance, and seemingly limitless potential. The scale of what lay before them often defied easy description.

Thirty-year-old Captain Daniel Livermore of the 3^rd New Hampshire explained how the land revealed itself.

“This morning the troops cross the east branch, coming on to the flats called Genesee Flats,—the most beautiful flats I ever saw, being not less than 4 miles in width, and extending from right to left as far as can be seen; supposed to be 15,000 acres in one clear body.”¹⁰

Livermore’s admiration was rooted in direct observation. The lush plain before him was not hypothetical potential. It was already producing extraordinary harvests. The river that nourished this abundant landscape wound quietly through the Genesee Valley. His journal attests, “The fields of corn are beyond account, there being not less than 700 acres in the place. The river that runs here empties into Lake Ontario, and good bottoming almost any time of year.”¹¹

And therein lies the irony of the Sullivan campaign. Through generations of cultivation, the Seneca had demonstrated the rich agronomic potential of Western New York. For all their admiration of what they found, however, Sullivan’s soldiers understood military necessity required its destruction.

They burned the corn. They cut down the orchards. They razed the villages.

Yet they preserved what they saw in their journals. Lieutenant Colonel Adam Hubley left perhaps the expedition’s most vivid description of the Genesee Flats.

“…the whole crossed a branch of the Jenise river, and moved through a considerable swamp, and formed on a plain the other side, the most extensive I ever saw, containing not less than six thousand acres of the richest soil that can be conceived, not having a bush standing, but filled with grass considerably higher than a man. We moved up this plain for about three miles in our regular line of march, which was a beautiful site, as a view of the whole could be had at one look, and then came to Jenise river, which we crossed, being about forty yards over, and near middle deep, and then ascended a rising ground, which afforded a prospect which was so beautiful that, to attempt a comparison, would be doing an injury, as we had a view as far as our eyes could carry us of another plain, besides the one we crossed, through which the Jenise river formed a most beautiful winding, and, at intervals, cataracts, which rolled from the rocks, and emptied into the river.”¹²

The Sullivan Expedition lasted only a few weeks within a war that stretched nearly eight years. Still, Sullivan’s soldiers brought their memories home with them. Among the stories carried home after the campaign were those of Major John Burrowes, whose account of the Genesee Flats must have sounded almost unbelievable to listeners back home.

“The army being now all crossed the march begins again and proceed across a plain about two miles and a half wide (some places wider) and to all appearance in length about 12 miles. Not a rise of ten feet through the whole, not a stump on it. a few acres of timber which stands in small groves make it appear much more beautiful. The land cant be equalled. I have frequently heard the expression when a person has been describing good grass and good pasture that it was knee high, and pasture up to the horses eyes, but here it is higher than a mans head when on his horse. When we marched through the plain we came to the Chenesee river, which we ford being about middle deep and the current very strong. This river empties itself into Lake Ontario and makes the falls of Niagara.”¹³

For all its bearing on the Revolutionary War, the Sullivan Expedition produced a far greater impact. It made the public aware of this new Genesee Country. The region was no longer an unknown blank on some colonial map.

Thousands of patriots now possessed firsthand knowledge of its beauty and its practical utility. Their journals preserved those impressions long after the war ended. In at least one case, the story came full circle. Major John Burrowes never settled in Western New York himself, but several of his descendants eventually did.¹⁴ What happened within one family mirrored a larger movement. The men who marched through the Genesee Valley carried home more than military memories. They carried home a vision of opportunity.

Sullivan’s soldiers may have marched into the new frontier to avenge the terror wrought upon western settlers by the Tories and their menacing allies. But they returned having accomplished something entirely unexpected—and unintended. They revealed a fertile country that would one day capture the imagination of settlers, speculators, and statesmen alike.

But seeing the Genesee Valley and possessing it were two very different things. You might assume the Paris Peace Treaty of 1783 solved everything when it effectively ended the Revolutionary War.

It didn’t.

The maps may have suggested that the United States owned this frontier.

Reality proved far more complicated.

¹ Beatty, Erkuries, Journal of Lieut. Erkuries Beatty, in Frederick Cook, ed., Journals of the Military Expedition of Major General John Sullivan Against the Six Nations of Indians in 1779 (Knapp, Peck & Thomson, 1887), p. 32.
² Col Erkuries Beatty, https://www.findagrave.com/memorial/65366577/erkuries-beatty [retrieved, May 25, 2026].
³ Beatty, p. 15.
⁴ Burrowes, John, Journal of Major John Burrowes, in Frederick Cook, ed., Journals of the Military Expedition of Major General John Sullivan Against the Six Nations of Indians in 1779 (Knapp, Peck & Thomson, 1887), p. 43.
⁵ Dearborn, Henry, Journal of Lieut.-Col. Henry Dearborn, in Frederick Cook, ed., Journals of the Military Expedition of Major General John Sullivan Against the Six Nations of Indians in 1779 (Knapp, Peck & Thomson, 1887), p. 77.
⁶ McKendry, William, Journal of Lieut. William McKendry, in Frederick Cook, ed., Journals of the Military Expedition of Major General John Sullivan Against the Six Nations of Indians in 1779 (Knapp, Peck & Thomson, 1887), p. 202.
⁷ Beatty, p. 31.
⁸ Hubley, Adam, Journal of Lieut.-Col. Adam Hubley, in Frederick Cook, ed., Journals of the Military Expedition of Major General John Sullivan Against the Six Nations of Indians in 1779 (Knapp, Peck & Thomson, 1887), p. 162.
⁹ Beatty, p. 32.
¹⁰ Livermore, Daniel, Journal of Captain Daniel Livermore, in Frederick Cook, ed., Journals of the Military Expedition of Major General John Sullivan Against the Six Nations of Indians in 1779 (Knapp, Peck & Thomson, 1887), p. 188.
¹¹ Ibid.
¹² Hubley, p. 162.
¹³ Burrowes, p. 48.
¹⁴ Ibid, p. 46.