The reason for that name is because this area has the highest terrain in Hòa Bình province and is the origin of many rivers and streams with large water reserves.

Also because of the uneven geographical characteristics and almost divided between villages, Lạc Sơn's economy has the lowest value in Hòa Bình province.

Those who make that cultural site were thought to have been settled by the researchers before the Xá refugees from Mai Châu moved to Ngọc Lâu [commune].

In addition, hang Xóm Trại ("the cave of the Farm hamlet") was soon recognized as a special archaeological monument from 2011 for finding a number of prehistoric stone tools.

The terrain of Lạc Sơn district is like an equilateral triangle that has two angles adjacent to Thanh Hóa province.

Lạc Sơn is divided into 24 commune-level sub-divisions, including the township of Vụ Bản and 23 rural communes : Ân Nghĩa, Bình Hẻm, Chí Đạo, Định Cư, Hương Nhượng, Miền Đồi, Mỹ Thành, Ngọc Lâu, Ngọc Sơn, Nhân Nghĩa, Quý Hòa, Quyết Thắng, Tân Lập, Tân Mỹ, Thượng Cốc, Tự Do, Tuân Đạo, Văn Nghĩa, Văn Sơn, Vũ Bình, Xuất Hóa, Yên Nghiệp, Yên Phú.