Square kilometre


The square kilometre is a multiple of the square metre, the SI unit of area or surface area. In the SI unit of area, 1 km2 is equal to 1M.
1 km2 is equal to:
  • 1,000,000 square metres
  • 100 hectares
It is also approximately equal to:
  • 0.3861 square miles
  • 247.1 acres
Conversely:
The symbol "km2" means 2, square kilometre and not k, kilo–square metre. For example, 3 km2 is equal to = 3,000,000 m2, not 3,000 m2.

Examples of areas of 1 square kilometre

Topographical map grids

Topographical map grids are worked out in metres, with the grid lines being 1,000 metres apart.
  • 1:100,000 maps are divided into squares representing 1 km2, each square on the map being one square centimetre in area and representing 1 km2 on the surface of the Earth.
  • For 1:50,000 maps, the grid lines are 2 cm apart. Each square on the map is 2 cm by 2 cm and represents 1 km2 on the surface of the Earth.
  • For 1:25,000 maps, the grid lines are 4 cm apart. Each square on the map is 4 cm by 4 cm and represents 1 km2 on the surface of the Earth.
In each case, the grid lines enclose one square kilometre.

Medieval city centres

The area enclosed by the walls of many European medieval cities were about one square kilometre. These walls are often either still standing or the route they followed is still clearly visible, such as in Brussels, where the wall has been replaced by a ring road, or in Frankfurt, where the wall has been replaced by gardens. The approximate area of the old walled cities can often be worked out by fitting the course of the wall to a rectangle or an oval. Examples include:
  • Delft, Netherlands
  • Lucca
  • Bruges
  • Chester United Kingdom

    Parks

Parks come in all sizes; a few are almost exactly one square kilometre in area. Here are some examples:
Using the figures published by golf course architects Crafter and Mogford, a course should have a fairway width of 120 metres and 40 metres clear beyond the hole. Assuming a 18-hole course, an area of 80 hectares needs to be allocated for the course itself. Examples of golf courses that are about one square kilometre include: