'Don't forget') is a regency (Indonesian: kabupaten) in the eastern part of Central Java province in Indonesia.

The rule was adopted pursuant to the treaty of Serat Perjanjian Dalem Natha entered into between Pakubuwono VII and the Dutch Government in the belief that the incumbent government was unable to fully function.

The six regions were the City of Surakarta and the then existent Regencies of Kartosuro, Klaten, Boyolali, Ampel and Sragen.

The regency covers an area of approximately 1,015.10 km2, with the highest point being Mount Merbabu - 3,141 m. Boyolali is located at the east foothill of Mount Merapi and Mount Merbabu, which has very beautiful and charming scenery, the spacious greens and hilly area around the volcanic activity of Merapi provides enchanting opportunities for sightseeing.

Boyolali also has tourist attractions in the form of a natural spring that flows continuously and very clearly, as well as water attractions, swimming pool, fishing pond and restaurants like the Tlatar (about 7 km north Boyolali city) and in District Pengging Banyudono (about 10 km east of the town of Boyolali).

(b) the 2010 population is included with the figure for Ampel District, from which the western part was cut out.

(c) the 2010 population is included with the figure for Musuk District, from which the southern part was cut out.