The Holland Land Company was an unincorporated syndicate of Dutch investors from Amsterdam, headquartered in Philadelphia, which purchased large tracts of American land for development and speculation. In operation in various iterations between 1789 and 1858, the syndicate's primary acquisition was of the western two-thirds of the Phelps and Gorham Purchase in 1792 and 1793, an area that afterward was known as the Holland Purchase. Additional lands were purchased in northwest Pennsylvania.

Aliens were forbidden from owning land within New York State, except by special acts of the New York State Legislature, so investors placed their funds in the hands of certain trustees who bought the land in central and western New York State. The syndicate hoped to sell the land rapidly at a great profit. Instead, for many years it was were forced to make further investments in their purchase; surveying it, building roads, digging canals, to make it more attractive to settlers. The syndicate influenced state policy in New York to allow foreign ownership of the land, avoid new taxes, and promote the construction of the Erie Canal and government roads on the company lands. It supported Governor Dewitt Clinton's faction in the state government to achieve these goals. The company finished selling its lands in New York in 1839, and in Pennsylvania in 1849, and was liquidated in 1858.

Company lawyer David A. Ogden purchased the pre-emption rights for the remaining Seneca reservation lands from the Holland Land Company in 1810 and established another unincorporated syndicate, the Ogden Land Company. It purchased much of the Seneca lands in the 1820s and 1830s, often fraudulently.

Dutch interest in American investments began during the American Revolutionary War (1775–1783). In 1789, four Dutch firms, Pieter Stadnitski and Son, Nicolaas and Jacob Van Staphorst, P. & C. Van Eeghen, and Ten Cate & Vollenhoven, joined and hired Dutch financier Theophile Cazenove as their purchasing agent to engage in land speculation. Cazenove's office, and later the company headquarters, were based in Philadelphia. The four houses soon expanded to six when they were joined by Willem Willink and Rutger Jan Schimmelpenninck in 1792, and established shares for the Holland Land Company in 1795. In 1791, Cazenove purchased 80,000 acres (320 km²) north of the Mohawk River and 120,000 acres (490 km²) in central New York, organized under the Cazenovia Establishment, on behalf of the four houses. In 1792, Cazenove arranged for the purchase of 1,500,000 acres (6,100 km²) in northwestern Pennsylvania on behalf of the six houses.

In addition to land, the Dutch investors bought American funds, including the South Carolina Funded Debt and the Massachusetts Deposit, and shares in the Pennsylvania Population Company. On the advice of Cazenove, they also obtained shares in canal companies in the years 1791–1792, including the Patowmack Canal, James River and Kanawha Canal, Santee Canal, Western Canal and the Connecticut Canal.

The tract purchased in Western New York was the portion of the Phelps and Gorham Purchase that lay west of the Genesee River. The aboriginal title to the land belonged to the Seneca Indians at the time. During the colonial era, New York and Massachusetts had both claimed pre-emption, the right to purchase the land from the Seneca, based on their colonial charters. In 1786, the two states negotiated an agreement in the Treaty of Hartford that would allow Massachusetts to retain the pre-emption right. Oliver Phelps and Nathaniel Gorham then purchased the pre-emption right from Massachusetts, but failed to extinguish the Indian title to this tract and defaulted on their purchase in 1790. Robert Morris next purchased the pre-emption right from Massachusetts in 1791 for $333,333.34 (about $6.32 million today). Morris was a signatory of the Declaration of Independence and a financier of the American Revolution, and at the time was the richest man in America. His purchase from Massachusetts was for some 3,750,000 acres (15,200 km²), divided into five parcels, which contained all lands west of the Genesee River except for the 185,000 acres (750 km²) of the Mill Yard Tract, which Phelps and Gorham retained along with their other lands east of the Genesee. He was soon pressed by his own debts and sought another purchaser for the land. He kept one parcel of 500,000 acres (2,000 km²) for himself in a tract 12 miles (19 km) wide and running the breadth of Western New York from Lake Ontario to the Pennsylvania border, known as the Morris Reserve. The right for the remaining four parcels, comprising the westernmost 3,250,000 acres (13,200 km²) was then purchased between December 1792 and July 1793 from Morris by the Dutch investors comprising the syndicate, through Cazenove and trustee Herman LeRoy.

Before Morris could give the Holland Land Company title to this land, it was still necessary to extinguish the Indians' title to it. This was achieved at the 1797 Treaty of Big Tree, executed on the Genesee River near modern-day Geneseo, south of Rochester, New York. Representatives of the Holland Land Company, Robert Morris's son Thomas, the Senecas, and a commissioner for the United States named Jeremiah Wadsworth gathered at Big Tree in August, 1797 and negotiations began. Mary Jemison attended as the leader of the Seneca, and proved to be an able negotiator. Chiefs and Sachems present included Red Jacket, Cornplanter, Governor Blacksnake, Farmer's Brother and about 50 others. Red Jacket and Cornplanter spoke strongly against selling the land. They held out for reservations, lands which the Indians would keep for their own use. After much discussion, the Treaty of Big Tree was signed Sept. 15, 1797. The native Indians were to receive $100,000 (about $1.9 million today) for their rights to about 3.75 million acres (15,000 km²), and they reserved about 200,000 acres (809 km²) for themselves.

In 1802, the boundaries of the Cattaraugus Reservation were adjusted and a strip of Seneca lands along the Niagara River was acquired by the company.