Jones Mill Branch is a long second-order tributary to Marshyhope Creek in Sussex County, Delaware.
Jones Mill Branch rises on the Bridgeville Branch divide about 0.5 miles northeast of Jacobs Crossroads, Delaware, and then flows generally west-northwest to join Marshyhope Creek about 1.5 miles east-northeast of Smithville, Maryland.
Jones Mill Branch drains of area, receives about 44.8 in/year of precipitation, and is about 6.55% forested.