The Northern Great Plains Section, Society for Range Management (formerly American Society of Range Management: 1948-1971) was organized January 24, 1950, following discussions beginning in January, 1948. Some members suggested each state (Montana, North Dakota, and South Dakota) form a section, leaving Canadian members to decide their own future. Other members called for a section based on commonality of regional rangeland characteristics and range management problems and practices. At Miles City, Montana, in November, 1949, members favoring a regional approach to sectional boundaries prevailed. A constitution and by-laws were established and submitted to the Society. On January 12, 1950, the constitution was approved by the Society Council, thus establishing the Northern Great Plains (NSP) Section.
The first constitution did not establish a specific boundary; it stated "...who reside in Montana, North Dakota, South Dakota, and Canada, and other Society members who are interested in the Northern Great Plains." Members from western Montana and Alberta requested a change in the definition of Section membership to permit their membership in the NGP Section. This proposal was rejected, leaving western Montana and Alberta members no choice but to establish a new section, the Northern International Mountain Section. That Section was renamed the International Mountain (IM) in 1950. In December, 1950, the South Dakota members of the Section concluded they had sufficient membership and interest to establish a state section. The South Dakota Section was established in 1950.
The western boundary of the Section has always been somewhat controversial. The boundary was not described in the first constitution and by-laws. In 1951, the two Section Councils (NGP & IM) met and agreed on a boundary description. This boundary left some "mountain country" in the NGP Section and some "plains country" in the IM Section. The GNP Section revised their constitution in 1968 to describe the boundary as "...a south-north line running through Chance, Bridger, Columbus, Big Timber, Harlowtown, Moccasin, and Great Falls, continuing north to include that part of Alberta lying east of the line running through Aden, Bow Island, Brooks, Settler, Camrose, and Edmonton." The IM Section met and revised their eastern boundary to essentially describe the same boundary. A new NGP boundary change was approved by both sections and the Society Board of Directors in 1994. It reads, "For administrative purposes, the NGP Section shall be considered to include the State of North Dakota, the provinces of Manitoba and Saskatchewan, and that part of Montana lying east from the eastern boundary of the following counties: Toole, Pondera Teton, Cascade, Meagher, and Park.
In the early 1960s fall group meetings of the NGP Section were organized in North Dakota, Montana, Alberta, and Saskatchewan, and were operational for a few years. In 1969, the Section had its first Chapter formed in North Dakota. The Yellowstone Chapter, south of the Missouri River, was formed in 1971 and the international Chapter, north of the Missouri River and centered around Swift Current, was formed in 1972. In 1980 a petition was submitted by members north of the Missouri River in Montana to form a Hiline Chapter and was accepted by the Section. In 1987, the Prairie-Parkland Chapter was formed in the province of Saskatchewan.
Membership has generally increased each year of Section existence. There were 104 members in 1951 with a 1995 membership of 315 making NGP Section the fourth largest. Two student chapters are official members of the Section. The Montana State University Chapter joined the Section in 1951 and the North Dakota State University Chapter joined the Section in 1982.