In relation to subnational flags, the rules are: gyronny or smooth field bearing coat of arms with five towers on the mural crown if the municipality or parish is headquartered in a city (cidade), quarterd or smooth field bearing coat of arms with four towers on the mural crown if the municipality or parish is based in a town (vila), and quartered or smooth field bearing coat of arms with three towers on the mural crown if it is a municipality based in a village (aldeia) or is an urban neighborhood of a town or city.

Also in accordance with the Portuguese heraldry, flags can be divided octagonally, hexagonally^{[examples needed]}, quarterly in saltire, cross or belt and still having the same color-field constants of the shield and the center estentendo stuff or a geometric figure where the coat of arms is applied.

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  Porto (gyronny)
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  Santo Tirso (smooth)
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  Resende (quartered)

An exception presented here is the flag of Lagos, which is divided per saltire (franchado), reflects the historical influence of King Manuel I in the region.

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  Lagos (franchada)
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  Personal Standard of King Manuel I

• Flag of Portugal
• Portuguese heraldry
• List of Portuguese municipal flags

• Bandeiras municipais e sub-municipais portuguesas