The plebiscites were held in two zones that were defined by Denmark[2] according to the ideas of the Danish historian Hans Victor Clausen.

The northern Zone I was delineated according to Clausen's estimation of where the local rural population identified itself as Danish, a survey published in 1891.

Tønder had a vast German majority (c. 80%) but was included in the northern Zone for geographical and economic reasons, and because of the small population of this (and the other) North Schleswig towns.

Since 1945, the North Schleswig Germans have been presented by Bund Deutscher Nordschleswiger, a cultural organisation, and continued to elect a member of Parliament until the 1950s.

This is a far smaller group than the 50,000 Danes who live in Southern Schleswig, where, for instance, Flensborg Avis, a newspaper in Danish, is printed every day.