French West Africa is the largest political grouping in tropical Africa, but the population is comparatively thin. In the area of nearly 1,800,000 square miles, stretching from Senegal to the Niger and Dahomey colonies, there are less than 15 million inhabitants; whereas the British colony of Nigeria has an area of roughly 370,000 square miles, but over 19 million inhabitants. Protestant missionary work is weak in French West Africa, compared with its strength in British territories, partly owing to the historic weakness of the French Reformed Churches, together with the difficulties experienced by English-speaking missionaries, which have given Protestant missions a very inferior place to Roman Catholicism.