The Holland Land Company was formed late in the 18th century by a group of Dutch investors to dispose of lands they had acquired west of the Genesee River, originally owned by the state of Massachusetts and the Seneca Nation of the Iroquois Confederacy until the 1797 Treaty of Big Tree.
The company had acquired them from Robert Morris, who had financed the Continental Army during the Revolutionary War, and needed to sell due to financial troubles in some of his other land dealings.
In 1794 they hired Pennsylvania surveyor Joseph Ellicott to survey the five million acres (2 million ha) they had acquired in what is now Western New York and the adjacent areas of Northwestern Pennsylvania.
After the survey was finished and the land subdivided into townships, Ellicott was appointed agent in 1800.

Working from the present site, Ellicott not only oversaw the sale of individual properties but functioned as the area's sole regional planner, reporting to Paolo Busti, the company's agent in Philadelphia, by mail.
He was, a contemporary historian wrote, "the single most powerful person in the area for the first two decades of the century."
His decision to sell the land in small parcels rather than large blocks, despite the objections of the company's trustees who wanted the land sold quickly, resulted in settlement by small farmers rather than the establishment of quasi-feudal manors as had occurred in the Hudson Valley.
Drawing on his experience laying out the city of Washington, D.C., for Pierre L'Enfant, he surveyed and planned the cities of Buffalo and Batavia.

The company's first office was a log cabin; Ellicott cleared the first tree on the site.
In 1809 it was replaced with a timber-frame building, in turn replaced by the existing structure in 1815, the third and last one.
It was built of stone to be fireproof and better protect the records it kept.
At that time it stood alone on a two-acre (8,100 m²) lot.
Ellicott left his position in 1820; the company remained in existence until the mid-1850s, by which time all the land had been sold and all the debts retired.

The building was eventually sold.
It became first a music school, and then a church.
To support those uses modifications were made to the interior.

In 1894 the Holland Purchase Historical Society was formed to restore the building and adapt it for museum use.
Later that year the building was dedicated to Morris's memory at a ceremony attended by Morris's descendants and members of the Cabinet of President Grover Cleveland, who had himself begun his political career in Buffalo.
It was staffed by members of the local Daughters of the American Revolution (DAR) chapter.

During World War II the DAR leased the building to the local chapter of the American Red Cross.
At that time the cinder block addition was built on the rear.
After the war, in 1948, the county's Board of Supervisors voted to assume ownership.

The western frame wing, known as the Robert Morris Wing, was added around 1970.
To build it and the parking lot, a house next door was demolished.
Seven years later it received an east wing, originally used by the county historian.
Since that office moved to separate quarters nearby it has been used for the museum.
The final addition came in 1982, a small room attached to the back of the wing's rear to exhibit the county's 12½-foot (3.8 m) gibbet.
The Holland Land Company was formed late in the 18th century by a group of Dutch investors to dispose of lands they had acquired west of the Genesee River, originally owned by the state of Massachusetts and the Seneca Nation of the Iroquois Confederacy until the 1797 Treaty of Big Tree. The company had acquired them from Robert Morris, who had financed the Continental Army during the Revolutionary War, and needed to sell due to financial troubles in some of his other land dealings. In 1794 they hired Pennsylvania surveyor Joseph Ellicott to survey the five million acres (2 million ha) they had acquired in what is now Western New York and the adjacent areas of Northwestern Pennsylvania. After the survey was finished and the land subdivided into townships, Ellicott was appointed agent in 1800.
Working from the present site, Ellicott not only oversaw the sale of individual properties but functioned as the area's sole regional planner, reporting to Paolo Busti, the company's agent in Philadelphia, by mail. He was, a contemporary historian wrote, "the single most powerful person in the area for the first two decades of the century." His decision to sell the land in small parcels rather than large blocks, despite the objections of the company's trustees who wanted the land sold quickly, resulted in settlement by small farmers rather than the establishment of quasi-feudal manors as had occurred in the Hudson Valley. Drawing on his experience laying out the city of Washington, D.C., for Pierre L'Enfant, he surveyed and planned the cities of Buffalo and Batavia.
The company's first office was a log cabin; Ellicott cleared the first tree on the site. In 1809 it was replaced with a timber-frame building, in turn replaced by the existing structure in 1815, the third and last one. It was built of stone to be fireproof and better protect the records it kept. At that time it stood alone on a two-acre (8,100 m²) lot. Ellicott left his position in 1820; the company remained in existence until the mid-1850s, by which time all the land had been sold and all the debts retired.
The building was eventually sold. It became first a music school, and then a church. To support those uses modifications were made to the interior.
In 1894 the Holland Purchase Historical Society was formed to restore the building and adapt it for museum use. Later that year the building was dedicated to Morris's memory at a ceremony attended by Morris's descendants and members of the Cabinet of President Grover Cleveland, who had himself begun his political career in Buffalo. It was staffed by members of the local Daughters of the American Revolution (DAR) chapter.
During World War II the DAR leased the building to the local chapter of the American Red Cross. At that time the cinder block addition was built on the rear. After the war, in 1948, the county's Board of Supervisors voted to assume ownership.
The western frame wing, known as the Robert Morris Wing, was added around 1970. To build it and the parking lot, a house next door was demolished. Seven years later it received an east wing, originally used by the county historian. Since that office moved to separate quarters nearby it has been used for the museum. The final addition came in 1982, a small room attached to the back of the wing's rear to exhibit the county's 12½-foot (3.8 m) gibbet.
Holland Land Office