Historically, the states that had the greatest interest in counting enslaved individuals as part of the population for representation purposes were the Southern states in the United States. This was part of the complex negotiations around the Three-Fifths Compromise during the Constitutional Convention of 1787.
Southern states, where slavery was a significant part of the economy and society, wanted enslaved people to be counted in the census to increase their representation in Congress and influence in the federal government. While enslaved individuals were not granted rights or representation, counting them as a fraction of the population (three-fifths) allowed these states to gain more political power relative to free states.
In contrast, Northern states were generally opposed to counting enslaved people for representation, as they had smaller slave populations and did not want to give additional political power to the slaveholding states. Thus, Southern states would have had the greatest interest in counting slaves for reputation and political representation.