Toronto radius map: 5, 10, 25 and 50 kilometre circles

A quick anchor for the scale. Ten kilometres from the centre reaches roughly to Thornhill, 12.2 km north. The furthest name in these tables is Oshawa, 49 km away to the east-north-east, and it still sits inside the outer circle. People underestimate that big ring every time, which is most of why this page exists.

One caution before you lean on the table. A GeoNames centre is a single point, usually somewhere near the historic core, and a city isn’t a point. Willowdale is listed at 6.7 km because that’s the gap between two reference points. Its nearer edge is closer than that, probably by a good margin.

Place names, coordinates and populations come from GeoNames, which the site uses under CC BY 4.0.

Area climbs with the square of the radius, and it catches people out every time. The 5 km disc around Toronto covers 79 km². The 25 km one covers 1,963 km², twenty-five times as much for five times the distance. By 50 km you’re looking at 7,854 km² of Ontario and whatever lies past its edges.

Put the two tables together and you get a crude density. Inside the 25 km circle there are about 4,217,716 listed people spread over 1,963 km², so roughly 2,149 per km². Crude is the right word. It counts GeoNames settlements only, so villages and open country vanish, and it treats a harbour or a reservoir as populated ground.

These are straight-line rings. That’s the right tool for a coverage question and the wrong one for travel time. A 30-minute drive out of Toronto comes out as a lopsided blob, an isochrone, racing down a motorway and stopping dead at a bridge. Drawing one properly takes a routing server. This site hasn’t got one, deliberately, because everything runs in your browser with no account and nothing uploaded.

Plenty of sites draw a plain circle, label it drive time and leave it there. Those are worth ignoring. A proper isochrone needs a road graph, turn restrictions and some idea of traffic, and it changes shape by the hour. What a circle gives you instead is a bound that doesn’t move: nothing outside the 25 km ring is within 25 kilometres of Toronto, whatever the roads do.

Where it all comes from. Names, coordinates and populations are GeoNames cities15000, which covers settlements of roughly 15,000 people and up. Anything smaller is simply absent. City subdivisions get stripped out on purpose, so a page about Toronto doesn’t fill with its own neighbourhoods instead of its neighbours. Distances are haversine on a 6,371.0088 km sphere, areas are spherical caps.

One oddity you’ll notice if you compare pages. Population counts come from GeoNames, which records what the national statistics office last published, so some are a few years old and a couple are more. They’re good for ranking and for rough sizing. The figure carried for Toronto is 2,794,356, which for some cities means the municipality and for others the whole urban area, so compare it with care.

What people actually use these rings for, roughly in order of how often it comes up: delivery and service areas, finding somewhere to live within a sensible distance of work, sizing a catchment for a shop or a clinic, checking how far an event’s noise and traffic will carry. Straight-line distance is the right first pass for all of them.