[1] The usual examples are counties (or equivalent sub-regional groupings) which are wholly subsumed by the municipal government within their boundaries.
[1] Similarly, the eight counties of Connecticut have only a shadow existence: virtually all of their governmental functions were abolished in 1960, the rest in 2000.
Their historic boundaries are used only to organize certain state level police and judicial districts.
However it has a well-established legal system without any other party effectively stating control over the region (and no likelihood of that changing in the anticipated future).
This means functionally ignoring a legal system of significance, from their point of view.