See title. Obviously the maximum base is determined by the perimeter, but the maximum height is not specified.
Yes there is and it differs between each settlement. The settlement boundaries are a box extending upwards towards the skybox but the ground height varies between settlements.
Crediting the above link, here are some examples;
- Sanctuary – 6 stories
- Tenpines – 3 stories (From the highest point)
- Starlight – 9 stories
- Greentop Nursery – 7 stories (From the level of the house)
…where “stories” is defined as a wall with a roof (with the next story being another wall on top with another roof, etc)