| Bayandelger District | |
| Native Name: | Баяндэлгэр сум |
| Native Name Lang: | mn |
| Settlement Type: | District |
| Subdivision Type: | Country |
| Subdivision Name: | Mongolia |
| Subdivision Type1: | Province |
| Subdivision Name1: | Töv Province |
| Timezone: | UTC + 8 |
| Utc Offset: | +8 |
Bayandelger (Mongolian: Баяндэлгэр, Rich wide) is a sum in the west of Mongolia's Töv Province. In 2005, it had 1226 inhabitants in 429 households.[1]
The sum was founded in 1923, under the name Gün sum and as part of the khoshuu of Darkhan Khoshoi Chin Wang Puntsogtsereng[2] in the Tüsheet Khan aimag. 1924 it was renamed to Batdelger uulyn sum, and in 1931 it was renamed again. In 1956 it was split between the Bayan and Erdene sums, with most of the territory going to the latter. In 1959, the Bayandelger sum was re-established.[3]
In 2004, there were 64,000 heads of livestock, including 19,000 goats, 35,000 sheep, 3,500 heads of cattle, 6900 horses and 71 camels.[4]
D. Natsagdorj was born in what is now Bayandelger sum.[2]