Cities near Castle Rock

What is this tool?

The Cities Near tool lets you explore all populated places within a chosen radius of any city in the world. Enter a city, pick a radius (50, 100, 200, or 500 km), and get an instant interactive map and ranked list — sorted from closest to farthest.

This is useful for trip planning, geography research, or simply satisfying your curiosity about what lies around a given city. The underlying dataset comes from GeoNames and covers 70,000+ populated places worldwide.

How does the distance calculation work?

Distances are calculated using the Haversine formula, which gives the great-circle distance between two points on a sphere — the shortest path over the Earth's surface. The result is accurate to within a few kilometres for most city pairs. Note that the Haversine formula assumes a perfectly spherical Earth; the true Earth is slightly flattened, so very long distances may differ by up to 0.5% from the exact geodetic distance.

Cities near famous places

• Within 100 km of Paris: Versailles, Chartres, Reims, Rouen — all classic day-trip destinations.
• Within 200 km of Tokyo: Yokohama, Kawasaki, Sagamihara, Chiba, Shizuoka — the vast Kantō metropolitan area.
• Within 500 km of Istanbul: Ankara, Bursa, Thessaloniki, Sofia, Izmir — crossing into three countries.