Dry counties, local option and why the map has holes
Texas has counties where you cannot buy a drink, and the register shows it.
State law sets the outer limit of what is permitted. Local voters set what actually happens, and in Texas they do it at a remarkably fine grain.
How local option works
Texas lets voters decide alcohol rules by county, by justice precinct, and by city — and they can decide different things for different categories. A jurisdiction can permit beer and wine off-premises while prohibiting spirits, or allow on-premises sales only by private club.
What that produces
Not a binary wet/dry map but a patchwork, sometimes changing at a city limit. It is why the private club permits (N, NB, NE) exist and why they cluster in specific places — they are the workaround where ordinary retail sale is prohibited.
Reading it in the data
Compare licence counts per county against population. A county with very few retail permits and a visible cluster of private club registrations is telling you about its local option status without any separate source. The Texas county breakdown makes this visible.
Elsewhere
New York and Connecticut have far less local variation in what is permitted, but both apply strong locational rules — proximity to schools and places of worship, density limits, municipal zoning — that shape where a licence can exist at all.