Representative dairy farms were modeled using the Integrated Farm System Model with 20 farms in each of 6 regions of the United States for the years of 1971 and 2020 to determine improvements made in reducing environmental impacts over the 50-year period. Important data and information describing these farms are documented in these tables. These data include the farm location, number of cows and heifers maintained, milk produced, feeds and nutrient contents fed, crop areas, crop yields, fertilizer and lime application rates, irrigation water applied, milking and housing facilities, manure collection, storage and application methods used, and soil characteristics. These data are published as supplementary information for the article “Fifty years of environmental progress for United States dairy farms” published in the Journal of Dairy Science.