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Early research at the Northern Great Plains Research Laboratory (NGPRL) near Mandan, ND focused on the ecology and management of native grasslands. In 1916, agronomist J.T. Sarvis began a stocking rate experiment on 250 acres of native mixed grass prairie at NGPRL. Part of that experiment continues today. Our objective is to document and present the origin, evolution, and scientific outcomes from this nearly century-old experiment. The central question was how many acres of native prairie were necessary to support a beef steer during the grazing season. In 1916, four pastures of 30, 50, 70, and 100 acres were laid out and stocked at one beef steer per 3, 5, 7, and 10 acres, respectively. The 30-acre pasture was expected to be overgrazed and the 100-acre pasture was expected to be undergrazed. Pastures were stocked continuously from May until October each year. The experiment was designed and conducted before modern principles of experimental design and replication were common. Sarvis, however, realized the need for controlling variables and chose an experimental site that was very uniform in slope, soils, and vegetation. Initial (30 year) results indicated that a moderate stocking rate (7 acres/steer) was sustainable on the northern Great Plains mixed grass prairie. In addition to answering the initial question, select pastures have been used to address additional diverse research questions dealing with drought, soil quality, greenhouse gas emissions, invasive species, and climate change during the history of this experiment.