Arnprior is a town in Renfrew County, in the eastern portion of Southern Ontario, Canada. It is located at the mouth of the Madawaska River, as it enters the Ottawa River in the Ottawa Valley. The town is a namesake of Arnprior, Scotland, and is known for lumber, hydro power generation, aerospace, farming and its proximity to the national capital region.

In May 1613 European explorers, led by Samuel de Champlain, first visited the Ottawa River valley, home of the Algonquin tribe of native North Americans.

In 1823, a 1,200-acre (4.9 km²) surveyed block was ceded to Archibald McNab and given the eponymous name, McNab Township. McNab had approval from the Family Compact to treat the settlers on his land in the feudal manner practiced in Scotland. In 1831 the town was named by the Buchanan Brothers after McNab's ancestral home of Arnprior, Scotland.

Tired of the harsh treatment, the settlers revolted and, after a government investigation, McNab was forced to vacate the area in 1841. Arnprior, Braeside and NcNab township grew as separate communities and boomed when they became incorporated into eastern Ontario's massive timber industry.

Ontario /ɒnˈtɛərioʊ/ is one of the provinces of Canada, located in east-central Canada. It is Canada's most populous province or territory and fourth largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa.

Ontario is bordered by the province of Manitoba to the west, Hudson Bay to the north, Quebec to the east, and to the south by the U.S. states of Minnesota, Michigan (portions to the west), New York (portions to the east), Ohio and Pennsylvania. All but a small part of Ontario's 2,700 km (1,677 mi) border with the United States follow inland waterways: from the west at Lake of the Woods, eastward along the major rivers and lakes of the Great Lakes/St. Lawrence River drainage system. These are the Rainy River, the Pigeon River, Lake Superior, the St. Mary's River, Lake Huron, the St. Clair River, Lake St. Clair, the Detroit River, Lake Erie, the Niagara River, Lake Ontario, and along the St. Lawrence River from Kingston, Ontario to the Quebec boundary just east of Cornwall, Ontario.