In ancient times, the largely unsettled territory was the traditional homeland of the now-extinct Wenrohronon Indians.

This was an enormous county, including the northern part of New York as well as all of the modern-day state of Vermont and, in theory, extending westward to the Pacific Ocean.

The eastern boundary of Tryon County was approximately five miles west of the present city of Schenectady.

In the years before 1776, most of the Loyalists in Tryon County fled across the Niagara Frontier into modern day Ontario, Canada.

In 1784, following the peace treaty that ended the Revolutionary War (and a treaty with Massachusetts that finally settled who owned Western New York), the name of Tryon County was changed to Montgomery County in honor of the general, Richard Montgomery, who had captured several places in Canada and died attempting to capture the city of Quebec.

This included Iroquois territory in New York; the four nations that had been allies of the British mostly relocated to Ontario, Canada where the Crown gave them land grants in some compensation for losses.

The Treaty of Canandaigua, in 1794, extinguished what was left of native title, with the exception of several reservations, three of which were at least partially located in what is now Cattaraugus County.

The name "Cattaraugus" derives from a Seneca word for "bad smelling banks," in reference to the odor of natural gas leaking from rock seams.

After 1860, in response to the construction of a railroad (where the Pat McGee Trail is now), the county seat was moved to Little Valley.

South of Salamanca, New York, a small city located within the reservation, is Allegany State Park, which is contiguous with the Allegheny National Forest in Pennsylvania.

The southern part of Cattaraugus County is the only area of western New York that was not covered by the last ice age glaciation.

It is noticeably more rugged than neighboring areas that had peaks rounded and valleys filled by the glacier.

The entire area is a dissected plateau of Pennsylvanian and Mississippian age, but appears mountainous to the casual observer.

Southern Cattaraugus County is part of the same oil field, and petroleum was formerly a resource of the area.

A continental divide between the Mississippi River and Great Lakes watersheds runs through Cattaraugus County.

Intercity bus service is provided through Coach USA, which runs through the county on its twice-daily Jamestown to Olean route (with connections to Buffalo and New York City).

Trailways offers a once-daily north-to-south run between Buffalo and points south in Pennsylvania.

This system was imposed in the 1960s in the wake of the one man, one vote federal court rulings of the era; before this, the county operated under a true board of supervisors model.

In 2008, the county voted for the Republican presidential candidate, with John McCain defeating Barack Obama by a 55-44% margin.

In 2010, Republican Carl Paladino carried Cattaraugus County over Democrat (and eventual winner) Andrew Cuomo 65% to 31%.

Limestone voters approved dissolution into the Town of Carrollton in September 2009; that took effect at the beginning of 2011.

Two geological formations, both called "Rock City," have the appearance of a town laid out with streets.

[19] A portion of this community maintains an exceptionally older order that eschews indoor plumbing, which, combined with a small number of Seneca who still live on traditional subsistence, gives the county a high rate of homes without indoor plumbing compared to nearby counties.

A branch of Jamestown Community College, in Olean provides higher education for residents.