The current population is 204,668. The metropolitan area, which includes the neighbouring cities of Waterloo and Cambridge, has 451,235 people, making it the eleventh largest Census Metropolitan Area (CMA) in Canada and the fifth largest CMA in Ontario. It is the seat of the Waterloo Regional Municipality, and is adjacent to the smaller cities of Cambridge to the south, and Waterloo to the north. Kitchener and Waterloo are often referred to jointly as "Kitchener-Waterloo" (K-W), although they have separate municipal governments. Including Cambridge, the three cities are known as "the tri-cities".

The City of Kitchener covers an area of 136.86 square kilometres. In 2004, the city celebrated its 150th anniversary.

Kitchener is located in Southwestern Ontario, in the Saint Lawrence Lowlands. This geological and climatic region has wet-climate soils and deciduous forests.

Within this part of Ontario, Kitchener is the largest city situated within the Grand River watershed. Just to the west of the city is Baden Hill, in Wilmot Township. This glacial kame remnant formation is the highest elevation for many many miles around. The other dominant glacial feature is the Waterloo Moraine, which snakes its way through the region and holds a significant quantity of artesian wells, from which the city derives most of its drinking water. The settlement's first name, Sandhills, is an accurate description of the higher points of the moraine.