Arnprior.

Arnprior is an Ottawa Valley town at the confluence of the Madawaska and Ottawa Rivers, just upstream of Ottawa, where the Ottawa River reach widens into Lac des Chats. The town's downtown waterfront runs through Robert Simpson Park — shoreline trails, a beach, and the Arnprior Marina at the foot of John Street — and the Madawaska enters the Ottawa at the eastern edge of town.

Immediately south of downtown sits Gillies Grove, an old-growth eastern white pine forest on Nature Conservancy of Canada land within the municipal boundary. NCC reports a documented tree in the grove at roughly 47 metres — one of the tallest known eastern white pines in Ontario — and walking trails wind through old-growth pine and mixed forest with interpretive signage.

The Algonquin Trail — the eastern segment of the Ottawa Valley Recreational Trail on the former Canadian Pacific Railway corridor — passes through Arnprior with a town trailhead, linking eastward toward Smiths Falls and westward toward Mattawa. The Arnprior & McNab/Braeside Museum on Madawaska Street interprets the McLachlin Brothers lumber era and the Gillies family backstory tied to the grove.

Arnprior sits on the traditional territory of the Algonquin Anishinabeg.