The harbour is protected by forts and there is a garrison in the town.
In 1906 the population of the commune of Algiers was 154,049; the population municipale, which excludes the garrison, prisoners, &c., was 145,280.
They were naval or military officers in command of the garrison, the convicts and the few free settlers.
In addition to this there is compulsory service in the National Guard (a) in the first class, consisting of men between seventeen and thirty years of age, liable for service with the standing army, and numbering some 15,000; (b) in the second class, for departmental service only, except in so far as it may be drawn upon to make up losses in the more active units in time of war, consisting of men from thirty to forty-five years of age, and (c) in the third class, for local garrison duty, consisting of men between forty-five and sixty years old.
Gemina against the Welsh hill-tribes, its garrison was soon removed and it became a flourishing town with stately town hall, baths and other appurtenances of a thoroughly civilized and Romanized city.