I think it's pretty natural. The jurisdictions are set up so that similar geographic areas and populations are covered. In the US, this happens to be on the cou

I think it's pretty natural. The jurisdictions are set up so that similar geographic areas and populations are covered. In the US, this happens to be on the county level in larger states, and at the state level in smaller states. It can also be at the city or town level. In the SF bay, SF itself is a city and county. The other counties have health authorities, but so does the city of Berkeley. All the health officers of the Bay Area counties are working together, so effectively creating a larger jurisdiction. But Los Angeles is 400 miles (600km) away and in a totally different situation, so it makes sense to do things locally in large states such as California. Different levels of jurisdiction allow for flexibility, so for example, the state may declare non-essential businesses closed, but the local health officer can define the list of essential businesses or activities--or issue exemptions. It also allows some level of local control. Smaller less-populated counties in Northern California where the population is more against the quarantine rules, and where frankly there is less need for them, can have less enforcement, or change later if they find they need it. For a different example, look at France, a highly centralized government. The central government makes all health decisions, but they they still divided the country into zones (Paris and the east were hardest hit by the virus). While all areas had restrictions, they were more strict in those regions, and now that they are starting to re-open, each department has a list of criteria. So each department will have different levels of openness, just like counties in the US.