It nearly corresponds with the Arrondissement of Dunkirk (the northwestern quarter of the Department of Nord) but with the some areas of the arrondissement falling outside Westhoek while some areas of traditional Westhoek lie in the neighbouring Department of Pas-de-Calais.
It was once the dominant language of the region, but a long-time policy of Francization, starting with the introduction of French as the language of education in 1853, has led to the replacement of Dutch with French in the region.
Of the population of the approximately 380,000 inhabitants of French Westhoek, there are now between 10,000 and 20,000 daily speakers of West Flemish, many of whom live in the arrondissement and city of Dunkirk, and twice as many who occasionally use the dialect.
The French Flemish dialect has had significant influence on local toponyms.
For example, the French Westhoek towns of Robecq and Dunkirk are derived from the Flemish names of Robeke and Duinkerke.