Polytopia Wiki

A city that requires nine more population to upgrade

The population of each city is used to determine city upgrades and the number of units the city can support. Every city has a set of population bars under its name representing how much population the city needs to upgrade. The amount of population required to upgrade a city is one more than the city's current level, e.g., it takes two population to upgrade a city from level 1 to level 2. How much population a city currently has is represented by the number of filled-in (blue) population bars.

Population can be gained by harvesting resources, constructing buildings, or forming city connections. If a building is destroyed or a city connection is lost, then the population it produces will also be lost. A city may have negative population, shown as red population bars. (This typically occurs to a former capital that has lost the population produced from city connections.) Each negative population decreases the income the city produces by one star per turn up to the point where the city no longer produces any income. A city cannot produce negative income. However, negative population does not impact the number of units a city can support.

The number of units supported by a city is indicated by dots inside population bars. A city may support as many units as its level, plus one. The unit which captures a village or a city will migrate from their original origin city to the one they are currently on. Units gained from ruins will inherit the origin city of the exploring unit, but will not count towards the population supported by the city. Upon capture, units produced from a city will not disappear, but they will lose their origin city. If the city is captured back, the units will not count again towards the supported population. This effectively allows a potentially infinite number of units.

It is theoretically possible (barring technical limitations) for tribes other than ∑∫ỹriȱŋ to produce infinite population using captured Sanctuaries, which attract wild animals that can then be hunted. However, this produces population too slowly to be practically useful.

Item Population Cost (stars) Population per star Stars per population Unlocked by
Harvest fruit 1 2 0.5 2 Organization
Hunt animal 1 2 0.5 2 Hunting
Fishing 1 2 0.5 2 Fishing
Lumber Hut 1 3 0.33 3 Forestry
Grow Forest & Lumber Hut 1 8 0.14 8 Forestry & Spiritualism
Sawmill 1 per friendly adjacent Lumber Hut 5 Varies Varies Mathematics
Farm 2 5 0.4 2.5 Farming
Burn Forest & Farm 2 7 0.286 5 Chivalry & Farming
Grow Forest, Burn Forest & Farm 2 12 0.165 7.5 Spiritualism, Chivalry & Farming
Windmill 1 per friendly adjacent Farm 5 Varies Varies Construction
Fungi 1 every turn, for 3 turns 5 0.6 1.66 Farming (modified)
Mine 2 5 0.4 2.5 Mining
Forge 2 per friendly adjacent Mine 5 Varies Varies Smithery
Port 1 7 0.14 7 Sailing
Outpost 1 5 0.2 5 Frostwork
Temple 1 20 0.05 20 Free Spirit
Water Temple Aquatism
Mountain Temple Meditation
Ice Temple Polarism
Grow Forest & Forest Temple Spiritualism
Forest Temple 15 0.07 15
City connection 1 in both the capital and connected city Varies Varies Varies Roads[note 1]
City upgrade to level 4 3 - - - -
Monuments 3 - - - Various


  1. City connections may be formed using Ports or Outposts only if one of them can be placed adjacent to the capital.