American Enclaves
A handful of American addresses have organised themselves around a single principle: that money is best spent on not being seen. Hedges, gates, ferry-only access and ordinances against pavements do the work that walls did elsewhere, and the interest for a visitor is in reading the rules rather than the houses.
The American enclave is a legal object before it is a social one. What separates these places from expensive neighbourhoods elsewhere is incorporation: they are their own municipalities, with their own police, zoning boards and school districts, and the boundary on the map is a boundary of law.
The mechanism is consistent. A wealthy area incorporates to control what gets built and who provides services, which keeps the tax base inside the line and the density outside it. Beverly Hills voted against annexation by Los Angeles in 1923, with Douglas Fairbanks and Mary Pickford campaigning, and has run its own police and schools ever since. Atherton has no commercial district at all — no shops, no office, one restaurant — because the zoning permits almost nothing but houses on one-acre lots. Fisher Island has no bridge and cannot be reached except by its own ferry.
That legal separateness produces the visible things people notice: the hedges, the absence of pavements in some of them, the private beaches, the security patrols answering to a village of three thousand. It also produces the numbers — several of these municipalities are among the highest-income places in the United States, and one or two are the highest.
None of this is hidden, which is the American part. In Europe this kind of separation is usually informal and old. Here it is written down, voted on, mapped and enforceable, and the enclave will tell you its median income if you ask.