The population of the region was 1,123,307 in 2016; however, this number does not include large numbers of seasonal cottage country residents, which at peak times of the year swell its population to well in excess of 1.5 million. Although it contains many small and medium-sized urban centres, much of Central Ontario is covered by farms, lakes (with freshwater beaches), rivers or sparsely populated forested land on the southern edge of the Canadian Shield.
Central Ontario is located within Southern Ontario. The Parry Sound territorial or judicial district and Muskoka district municipality are geographically within Central Ontario, but are treated as part of Northern Ontario by federal economic development programs because of these districts' special economic circumstances. Parry Sound, but not Muskoka, is now classed administratively with an extended Northern Ontario region by the provincial government for reasons similar to those at the federal level.
All or part of Grey County and Bruce County may on occasion be included with Central Ontario as they are north of 44 degrees in latitude but are far more often treated as part of Southwestern Ontario or the Georgian Triangle area, which includes parts of both Central and Southwestern Ontario. Hastings County and Prince Edward County may be considered part of Central Ontario by different sources but are more often included with Eastern Ontario, mostly because they share the same telephone area code (613), have better transportation links to this region, and are part of the coverage area of Kingston-area media.
The southern portion of the region is more densely populated than the northern portion, as this area is closer to the GTA and hosts cities such as Barrie, Peterborough and Belleville (the latter bordering on Eastern Ontario). All three cities serve as regional centres, Barrie and Peterborough having strong economic ties to the Greater Toronto Area. Barrie in particular has a fast-growing population as a result of the GTA's northern encroachment and has benefited economically from its key position in close proximity to Toronto. Both Barrie and Peterborough are also located in the Greater Golden Horseshoe region.
The Canadian Shield runs over the northern part of Central Ontario, a recreational area with a much increased summer-time population, including the wilderness of Algonquin Provincial Park. Often referred to as 'Cottage Country', this area's lakes and rivers are dotted with numerous cottages, some of them seasonal, but in recent years there is a growing trend for some of these 'summer cottages' to be used as year-round residences due to a number of factors, abundance of outdoor recreation, baby-boom retiree population, increased local services and improved wireless communication.
The Trent-Severn Waterway, constructed over many years in the mid-19th century, spans Central Ontario via a series of boat locks, connecting Georgian Bay with Lake Ontario, entering the bay at Port Severn and Lake Ontario at the Trent River on the Bay of Quinte at Trenton(access to Lake Ontario also can be had by using the Murray Canal). Bypassing many rapids, this world-renowned waterway is used by pleasure boaters and anglers during the summer months.
Along the northern edge of Central Ontario, are some of the highest elevations in Southern Ontario. These highlands are known as the Opeongo Hills, and they stretch into portions of Eastern Ontario as well.
The climate of this area is a Humid continental climate with large seasonal variation moderated somewhat by the Great Lakes. Summers are warm and humid (sometimes hot) but are shorter than further south with generally cooler nights. Winters are cold with significant snowfalls; some snowbelt areas receive an average of over 300 cm (120 in.) per year. Severe summer storms are also commonplace, particularly in Simcoe County which for Ontario has a high tornado prevalence and was the site of the infamous Barrie Tornado in 1985.