Halton Hills.

Halton Hills sits on the Niagara Escarpment between Caledon and Milton in the western Greater Toronto Area, made up of Georgetown, Acton, Glen Williams, Limehouse, and Norval. The Bruce Trail — Canada's oldest and longest marked footpath — runs through three Credit Valley Conservation areas inside the town: Limehouse, where the trail passes through the 1860s Lime Kilns ruins and the Hole in the Wall escarpment crevice; Silver Creek, where it threads more crevice caves and Carolinian forest; and Terra Cotta, with mature hardwood forest and a stocked rainbow trout pond.

The Credit River carries brown trout and migratory steelhead through Norval and Glen Williams, where the 19th-century woollen mill village around Williams Mill Creative Arts still anchors the river bend. Conservation Halton's Hilton Falls Conservation Area, on the town's southern boundary with Milton, drops a 10-metre cascade where Sixteen Mile Creek crosses the escarpment past the 1820s ruins of Hilton's mill.

The Niagara Escarpment was designated a UNESCO World Biosphere Reserve in 1990. Halton Hills sits on the traditional territory of the Mississaugas of the Credit First Nation.