City range

When picking a location for a new city, make sure to check how many regions are adjecent to the your selected location. Most have about 6, but that number can vary.

3 adjecent regions
8 adjecent regions

The city range visible on the city screen shows nearby regions that can be exploited. Every city can work the regions directly adjacent to it - as long as they belong to your kingdom.

range3.jpg

Increasing city range

It's possible to exploit regions in a distance of 2 from the city - as long as that region is within your kingdom's borders and neighbours a city or village.

Using villages

If your city has a palisade or other fortification, then a village belonging to your kingdom will allow your peasants to work on the regions neighbouring the village - as long as those regions are within a distance of 2 from the city.

range4.jpg

Apart from basic villages, it's possible to use advanced villages in a similar fashion - the mill, forester's lodge and mining settlement. Apart from allowing you to work additional regions, they improve resource yield from neighbouring areas - food, furs and iron ore respectively.

Using another city

If one of your cities (A) has a fortification, and another city (B) is at a distance of 3 regions from it, then city A can use regions within a distance of 2 that neighbour city B. It's easier to explain that on a screenshot:

range5.jpg

And vice versa - city B can use regions within a distance of 2 from it that neighbour city A:

range6.jpg

Coastal cities

Additionally, any coastal city with a fortification can build a harbor or port to extend the city range over all sea regions within a distance of 2.

City range extended with villages on land and a harbor on the sea

It's possible to use villages to be able to work sea regions, but usually a harbor is more convenient.