Event Permit
Large Travis County Events May Need Fire Marshal Permits
Throw a sizable event out past the city limits, where county review applies, and the Travis County Fire Marshal is the office you'll be dealing with. Event permits run through the fire marshal's permit portal, and the mass-gathering rules pull in their own thicket of requirements: fireworks, tents and membrane structures, stages, even drive-in concerts each have their own piece.
The part with teeth is the Emergency Preparedness Plan: assembly locations have to have one, with a single carve-out for assemblies used purely for religious worship under an occupant load of 2,000. So for a festival, concert, race, market, or private-venue gathering under county jurisdiction, call the Fire Marshal early. Tents, stages, and fire-access lanes are far cheaper to fix on paper than the week of the event.
Source to confirm: Travis County Fire Marshal - Special Event Permits