Template:F-us/doc

'''The above template is generally all that is needed on the editable part of a category page for "Families of Somesuch County, Mystate" in the United States. Just type or paste this:'''

 or  

(with appropriate local variations for county/borough/parish and state).

The template will probably be adaptable for Canada and for any province or state or even city of any North or South American country, using separate templates for each such country so that local variations of page naming can be accommodated (for example, so that the name of the country can be appended to the introductory sentence if it is not in the page name). Note the small differences between this and Template:Born in UK, where the county page name does not include the state.