Boriwen (Thai: บริเวณ) were subdivisions of three of the larger Thai monthon. Several mueang were grouped together into one boriwen. In 1908 the boriwen were renamed to changwat, which became the name of provinces countrywide in 1916.
The monthon with between three and five boriwen were Phayap, Udon Thani and Isan. Each boriwen was administrated by a commissioner (khaluang boriwen, ข้าหลวงบริเวณ). The administrative headquarters of the boriwen were located in the provincial town listed first: