Ithan Creek (also known as Ithan Run) is a tributary of Darby Creek in Delaware County, Pennsylvania, in the United States. It is approximately 4.2 miles (6.8 km) long and flows through Radnor Township and Haverford Township. The creek's watershed has an area of 7.39 square miles (19.1 km2) and is highly developed. It has three named tributaries: , , and Meadowbrook Run.