Dataset describes Kentucky bluegrass production and height throughout two growing seasons in a rangeland system in the northern Great Plains. One year of sampling was during a drought year and one year had average precipitation. 2017 was a drought year and 2018 was an average precipitation year. Dataset also includes the nutritive value of Kentucky bluegrass throughout the season. Dataset can be used for modeling or for grazing planning. Some plots were mowed before the growing season to simulate early defoliation. Sampling occurred at the USDA Northern Great Plains Research Laboratory near Mandan, ND (46.7673 N, 100.9184 W) The 6-hectare pasture is at an altitude of 502 m above sea level and is within the temperate steppe ecoregion of the United States. This region is characterized by long, cold winters and short, hot summers. Predominant soil types include Temvik-Wilton silt loams (fine-silty, mixed, superactive, frigid Typic and Pachic Haplustolls). The pasture is on a loamy ecological site (site ID 054XY030ND) and is managed as a native grassland with no fertilization or irrigation. The average soil texture is a clay loam (31% clay, 49% silt, and 20% sand). Average soil chemical characteristics were: pH (H2O) = 6.4; OM = 7.4% LOI; Na (ppm) = 8.25; K (ppm) = 362.4; Ca (ppm) = 1925.4; Mg (mmolc/dm3) = 417.6; CEC (me/100 g) = 17.5; S (ppm) = 8.3; Cu (ppm) = 0.74; Fe (ppm) = 33.7; Mn (ppm) = 18.5; and Zn (ppm) = 9.7. Data can be used for planning of animal grazing or for modeling grazing systems in the northern Great Plains of the USA.