Additionally, there are a number of hamlets and rural clusters within the town, including Ashgrove, Ballinafad (straddling the boundary with Erin), Bannockburn, Crewsons Corners (straddling the boundary with Erin, Guelph-Eramosa and Milton), Glen Williams, Henderson's Corners, Hornby, Limehouse, Mansewood, Norval, Scotch Block, Silver Creek, Speyside, Stewarttown, Terra Cotta (straddling the boundary with Caledon), and Wildwood.

[5] The town is bisected by the Niagara Escarpment from southwest to northeast, and a significant portion of the rural area is located within the provincial Greenbelt.

Brook trout had been eliminated from the Black Creek watershed for many years, following the ongoing environmental disaster due to the excessive consumption of faecal mater as well as the trailer park polluting the water in the town of Erin.

[10] The physiography[13] and distribution of surface material[14] in the Town of Halton Hills are the result of glacial activity which took place in the Late Wisconsinan Substage of the Pleistocene Epoch.

This period of time, which lasted from approximately 23,000 to 10,000 years ago, was marked by the repeated advance and melting back of massive, continental ice sheets.

The Escarpment, formed by erosion over millions of years, is a high relief bedrock scarp which trends to the north through the central part of the town.

The escarpment face exposes a complex succession of shales, sandstones, limestones and dolomites of the Clinton and Cataract Groups.

Red shales of the Queenston Formation underlie the eastern half of the town and are generally covered by more than 15 m of glacial sediments, predominantly the Halton Till.

[15] At Limehouse, rock from the Clinton formation yielded green and brown shales and blue marl, which were used in the manufacture of mineral paints.

[18] The town is located in an area that is considered to be of low seismic potential, and the largest recent earthquake to take place within its limits was of magnitude 3 on 29 June 1955.

[24] The hamlet of Hornby was home to the large Brain Brewery, established in 1845;[25] it was eventually making 5,000 barrels of beer per year with ten employees.

The largest visible minority groups were South Asian (5.6%), Black (1.7%), Chinese (1.2%), Filipino (1.0%) and Latin American (1.0%).

They are specifically described as follows:[42] The town has four main roads: East-west North-south Bus service is provided by GO Transit along Highway 7 on its Georgetown line corridor.

[43] Rail freight service is also provided by Canadian National on its Halton Subdivision from Georgetown southwest through Milton to Burlington.

In November 2020, VIA Rail Canada rerouted some of its trains onto the Halton Subdivision through Stewarttown while their usual route was closed for signal upgrades.

Halton Hills is also covered by the following local newspapers and online media: A radio transmitter in Hornby is used by stations CFZM and CJBC.