A) Persons or elements co-existing in the same politically or economically defined region. This refers to any geographical entity contained within a single set of borders, containing a maximum of one market town. For example, although Silistra in the Ottoman Empire is considered a single political entity (there are no smaller political subsections), the province is divided into six economic markets - so each individual market within Silistra is considered an independent locality.
B) Persons or elements co-existing in a single 20-mile hex, regardless of political borders. For example, the Free City of Offenburg, the County of Lahr, the County of Alsace, the County of Baden and the Duchy of Briesachgau all share a single hex the center of which is located 15 miles to the southeast of Strasbourg. All persons within this hex would be considered part of one locality.
C) Persons or elements co-existing within two or more cities that are less than 3 miles apart, even though they may be in different political entities or in different hexes. For example, although Roubaix, Wattrelos and Tourcoing are all located within the County of South Flanders, they are all within a mile or two of Mouscron, in the County of West Flanders.