County of Fortune population is not a number you manage directly: population follows the jobs you run. If a building has an open position, an immigrant from a neighbouring kingdom arrives and fills it.
County of Fortune population: the three things that control it
- Equipment. Supplying more equipment to a settlement raises the maximum number of workers its buildings can hold. Providing more recipes raises building efficiency in the same way. You need both if you want a settlement to hold more people. Building slots covers how the equipment reaches the settlement.
- Maintenance. Buildings are kept alive by carpenter's guilds and, at the higher tiers, by masons' guilds. If maintenance is not met a building breaks down, and a settlement whose buildings are falling apart stops attracting immigrants.
- Time. A new settlement needs to fill up. Even with all of its needs met, the first inhabitants can take a couple of in-game years to arrive, so a fresh village that is empty at the start is not broken.
Why a fully supplied settlement can show zero population
The usual reason a settlement that looks fully supplied still shows a population of zero is maintenance: the buildings are falling apart, so nobody moves in. Building maintenance covers how to keep them alive, and building slots covers the equipment side of the worker limit.
Reading the population panel
The settlement panel shows the current population, the settlement's own power, and how the vendors attached to it are doing — travelling versus idling, for example seven travelling and five idling. How many villagers a building employs differs by type; players report that the tavern employs more than most production buildings, so the mix of buildings you build affects how fast a settlement fills up.
Population also feeds the political and cultural layer: a culture's share of the regional population scales its Traditional Product bonuses, and the number of Commoners you attract is what widens the map into new regions. Cultures covers that link.