The soils and the climate of the Great Lakes and Cornbelt states dictate that drainage is required to carry out economically viable farming activities. When drained, the soils are very productive and this eight-state region accounts for nearly 80% of the agricultural production of the United States. Drainage played an important role in the development of the region and a historical perspective is included to indicate the impetus for drainage and the amount of drainage application. Research results of agricultural drainage effects on water quality indicate that agricultural subsurface drainage has both positive and negative impacts; i.e., reduction in sediment and phosphorous, and increase in nitrate-nitrogen delivery to receiving waters. Research is needed to evaluate the full potential of controlled drainage and water-table management systems for managing agricultural effects on water quality. This information is needed by state and federal agencies to help landowners meet existing and impending water-quality requirements. Drainage is an important management practice for improving water quality while sustaining agricultural viability.