Zone
A grouping of venues or areas that share an operational characteristic — a city cluster, a security perimeter, a transport region.
Why it matters operationally
Zones are how large events stay comprehensible. Eighteen venues is a list nobody can hold in their head; four zones of four or five venues is. They also tend to be the unit that operational responsibility is divided along, so they are the natural way to filter almost any question.
How Roadmap handles it
Every venue belongs to a zone, and zones carry through the venue map and the reporting filters.