[3] The land office building itself is a one-and-a-half–story limestone structure with a 47-by-36-foot (14 by 11 m) main block topped with an asphalt-shingled gabled roof.

A wooden pedimented entrance portico projects from the north (front) elevation, and two additions are located to the southwest.

[3] Four round stone columns support the pediment, where a denticulated cornice frames an entablature faced in clapboard.

Below the cornice are black letters spelling out "Holland Land Office Museum" on the plain frieze.

The two six-over-six double-hung sash windows on either side of the main entrance have louvered shutters with stone sills and splayed lintels.

[3] On either side of the pediment small gabled dormer windows with eight-over-eight double-hung sash pierce the roof.

[3] 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.

[3] 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.

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.

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.

[7] During World War II the DAR leased the building to the local chapter of the American Red Cross.

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.