Recent yield improvements in corn yield have been associated with increases in plant populations. Previous studies in the southeastern US have shown that high plant populations can lead to increased yield, but are often accompanied by poor stalk strength and barren plants. However, this problem could be overcome by increasing root volume through increased levels of potassium. By combining increased potassium fertility with management practices that increase early root growth a three-dimension root system could be developed that would support higher plant populations and high yield. The objective of this research was to examine the impact of increasing plant populations and at-planting fertility treatments on root volume and yield in corn. Eleven studies were conducted in eastern North Carolina over three years with the primary treatments consisting of four corn populations (49 400, 66 690, 83 980, and 93 860 plant ha^-1) and four fertility treatments utilizing different combinations of N, P, and K. Across all sites, corn yield increased with increases in plant populations. Corn yields at populations of 83 980 and 93 860 plants ha^-1 were always significantly greater than yields at the lower populations. However, significant yield differences were not always observed between the two highest population treatments. Root volume decreased significantly with increases in plant population. Fertility treatments improved root volume and yield with significant differences observed at most of the sites.