Inadequate water supplies throughout the growing season limit cotton yields on the Texas Southern High Plains by reducing fruit initiation and development. Proper plant densities can increase lint yields by reducing the risk of water stress during early fruit initiation and development. Increasing the water supply plant^-1 maximizes lint yield potential by maximizing fruit per plant and subsequent fruit m^-2, the major component of lint yield. Understanding the dynamics of fruit site production, retention and fruit size relationships as water supply varies is important in managing each cotton crop for maximum lint yields. Field studies were conducted over a three year period under a range of plant densities (5, 10, 15 and 20 plants m^-2) and several water supplies ranging from dryland to full irrigation. Water supply plant^-1 was calculated for four stages of development by dividing water supply m^-2 by plant density. Fruit site production, fruit retention, and boll size were determined at maturity. Fruit number at first, second and third fruiting positions from fruiting nodes 1 to 10 increased as water supply plant^-1 increased during the period from square initiation to peak bloom. First position boll numbers increased rapidly as water supply plant^-1 from square initiation to peak bloom increased, reaching a maximum at approximately 60 kg H₂O plant^-1. Second and third position bolls increased linearly as water supply plant^-1 increased. First and second position bolls at fruiting nodes 11 and above were unresponsive to changes in water supplies. Lint boll^-1 of first and second position bolls at fruiting nodes 1 to 10 increased as water supply plant^-1 increased from first flower to peak bloom. Lint boll^-1 of third position bolls at the same fruiting nodes declined as water supply plant^-1 increased. At fruiting nodes 11 and above, lint boll^-1 did not respond to increases in water supply plant^-1. Analysis of fruiting position and nodal group contribution to final lint yield plant^-1 indicated that as water supply plant^-1 increased, second position bolls becoming necessary to achieve lint yields above 650 kg ha^-1. Third position bolls and bolls produced at or above fruiting node 11 contribute less than 3% to the final lint yield plant^-1 regardless of the water supply plant^-1 . Based on the hypothesis that the ideal plant density within a given water supply is one that produces one-half of the maximum yield plant^-1, these results indicate that the ideal plant density is one that results in a water supply of 30-35 kg H₂O plant^-1 from square initiation to peak bloom. At this density, first position fruit numbers should be maximized, thereby maximizing fruit m² and subsequent lint yield.