Kemnay, Manitoba, emerged as a settlement in the late 19th century amid the broader wave of prairie homesteading that transformed the region's landscape following Canada's expansion westward. Homesteaders were drawn to the area around 1885 by the availability of fertile agricultural lands and the strategic proximity to expanding railway networks, which facilitated transportation and economic viability. The Canadian Pacific Railway's main line, completed nearby in the early 1880s, spurred initial settlement, with a branch line extending from Kemnay southward to Souris beginning construction in 1889.

The community's name reflects the strong Scottish immigrant influences prevalent in Manitoba's early pioneer population. Kemnay derives from the village of the same name in Aberdeenshire, Scotland, a nod to the heritage of settlers who brought their cultural ties to the new frontier. This naming convention was common among Scottish diaspora communities seeking to evoke familiar roots in their adopted homeland.

A pivotal early institution was the post office, which opened on July 1, 1887, and served as a central hub for communication, mail distribution, and social interaction among settlers until its closure on November 5, 1976. Complementing this, the Kemnay School District was formally established in July 1885, providing essential education to the growing population of pioneer families.

The community of Kemnay underwent notable infrastructural advancements in the late 19th and early 20th centuries, closely linked to railway expansion that spurred agricultural growth. Construction of the Souris Branch line began from Kemnay in 1889, enabling the first train to reach Souris on January 13, 1890, and thereby improving grain transport from local farms to broader markets. This development reinforced Kemnay's position as a key rail junction in the Rural Municipality of Whitehead, where fertile lands along the Souris River valley supported wheat production and homestead expansion. By 1904, the Canadian Pacific Railway had doubled its tracks to Kemnay, further solidifying the community's economic ties to agriculture through enhanced connectivity for settlers and produce.

Agricultural infrastructure advanced with the 1928 construction of a 34,000-bushel wooden grain elevator by Manitoba Pool Elevators on the CPR Broadview Subdivision in Kemnay, which operated until around 1968 and handled local grain storage and distribution under appointed agents. Educational facilities also evolved to meet growing needs; in 1897, a two-storey brick schoolhouse replaced the original 1885 one-room structure, providing dedicated spaces for elementary grades on the first floor and high school classes on the second. This building served until 1949, when it was supplanted by a new one-storey structure designed for grades 1 through 9, with older students bused to Brandon, marking a shift toward more efficient, single-level educational design.

In the mid-20th century, particularly post-World War II, Kemnay participated in regional modernizations that transformed farming and community amenities. From 1945 to 1965, Manitoba's agricultural sector entered a prosperous era characterized by rural electrification, expanded road networks, and mechanized practices that increased farm efficiency and output on mixed operations typical of the area. These changes aligned with Kemnay's agrarian focus, complementing facilities like the grain elevator. By 1967, the local school district integrated into the Brandon School Division, streamlining administration and resources amid these broader infrastructural and social evolutions.