The spreadsheet linked here provides the adult population for the 81 locations listed in the request.
In order to obtain these figures, we utilized precompiled information from the World Population Review and the US Census. This allowed us to keep an apples-to-apples comparison as much as possible. In situations where the US Census was used, the adult population was computed by obtaining the percentage of minors and subtracting that from the total population of the city. There are also several locations that span more than one city; in cases like those, we have provided the total adult population as well as a breakdown per city.