I apologize, but there seems to be an error in the information provided. The Mississippi River does not flow through or near the state of Mississippi. It is a major river that flows through multiple states in the United States, including Minnesota, Wisconsin, Iowa, Illinois, Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and Louisiana.

Therefore, I cannot provide accurate information about the boat ramp named Medford Millpond (Black River) in Mississippi as it does not exist. Could you please provide more accurate details or clarify the location?