[3] Because the Mu lies within the Dry Zone in the rain shadow of the Arakan Mountains, it receives scanty summer monsoon rainfall with a total streamflow of 350 millimetres (14 in).

[5] In 1503, the Mongyang State attacked and took the northern garrison town of Myedu that guarded the irrigated Mu Valley, an important granary to the Bamar Kingdom of Ava.

[6] The Kabaw Valley saw many an invasion by Manipur State to the west, most notably during the reign of Gharib Nawaz (1709–1748), when his army crossed over the Chindwin and the Mu, took Myedu, and reached as far as Sagaing opposite the capital Ava.

[7] Descendants from Portuguese captives, the Bayingyi, were taken by King Anaukpetlun after defeating the adventurer Filipe de Brito e Nicote and settled in the area in the 17th century, still keep their Roman Catholic faith.

[11] Large-leaved deciduous hardwood of the Dipterocarpus spp., mainly D. tuberculatus, dominates in the forests mixed with some ingyin (Pentacme suavis and Shorea oblongifolia), taukkyan (Terminalia elliptica), thitsi (Gluta usitata), bamboo, and kaing tall grass (Saccharum spp.)

There has been a decline in the population of large mammals since the end of World War II into the 1980s, and these include tiger, bear, leopard, gaur, banteng, dhole, muntjac and hog deer.