Formerly the Kingdom was divided into Muangs, about sixty in number, each dependent on Bangkok. The provincial muangs of the North and East were dependent on the Ministry of the Interior (Krasuang Mahadthai), those of the West on the Ministry of War (Krasuang Kalahom), those of the coast on the Foreign Office (Krom Tha), and Krung Thep on the Krom Muang. The change was made in the year R. S. 114, when all the civil affairs of the whole of the provincial muangs were placedunder the Ministry of the Interior, and every four or five muangs formed into a monthon, Monthon Krung Thep was placed under the administration of the Ministry of Local Government, and the rest of the country under that of the Ministry of the Interior
For administrative purposes the Kingdom is now divided into eighteen Circles (Monthon) which are subdivided into Provinces (Muang) according to importance, and these latter are again subdivided into districts (Amphur). With the exception of the metropolitan Circle of Krung Thep all monthons are under the Ministry of the Interior. If then the metropolitan Monthon be omitted, the general scheme of organisation may be summarized as follows At the head of each Monthon there is placed a Lord Lieutenant (Samuha Tesar Bhibaln), formerly known as High Commissioner, who is resident within his monthon and who is a representative of all the Ministers in Bangkok. At the head of each province there is a Governor, who is in the first instance responsible to the Lord Lieutenant of his Monthon. At the head of each Amphur is a Nai Amphur who is responsibleto the Governor. With the passing of the Local Administration Act seventeen years ago — introduced by H.R.H. Prince Damrong — the system of administration was completed, and it is working satisfactorily. Under this Act the province is, as just stated, divided into districts, each under a Nai Amphur; the district is again divided into Tambon or villages; and these latter are divided into Mu Ban or hamlets. At the head of every Mu Ban of from ten to twenty families is placed an elder (Phu Yai Ban), and these elders elect the Kamnan or headman of the whole village in which their Mu Ban are included. Thus from the small group of families up to the central Ministry which controls the system, there is complete responsibility for order and government. A general Administrative Conference of the Lords Lieutenant of the various Monthons is held in Bangkok each year, usually in September, when they discuss all new measures that are necessary to be taken in their respective districts.
For the repression of robberies in the provinces a gendarmerie has been established, under the Ministry of the Interior, in all the Monthons. This service has given general satisfaction.
The Revenue Department under the same Ministry is another departure of recent years, which has worked an important reform in the administration by relieving the executive officials of all handling of the revenues.