Hierapolis is mentioned only once in the New Testament. Paul commends Epaphras, who seems to be from Colossae, for his burdensome labor for the churches of the Lycus River Valley. He says,
For I bear him witness that he has worked hard for you and for those in Laodicea and in Hierapolis. (Col. 4:13 ESV)
The name Hierapolis means “holy city.” The modern Turkish name is Pamukkale, meaning “cotton castle” or “cotton fortress.” The city is famous for the hot springs and the limestone formations that cascade down the hillside below the city.
The Lycus valley is in extreme southwestern Phrygia, Asia Minor. Hierapolis is situated on a plateau about 600 feet above the valley floor. Hierapolis, Colossae, and Laodicea form a triangle in the valley. From Hierapolis to Laodicea is about 6 miles south. The sites can be seen across the valley. From Laodicea to Colossae is about 10 miles to the southwest. From Colossae it is about 12 miles to Hierapolis.
Click on the map for a copy large enough to use in a PowerPoint presentation. Detailed maps of the area around Hierapolis, Laodicea, and Colossae are not usually found in maps found in Bibles, or even atlases. I used Bible Mapper to make this map showing the three cities of the valley. The Lycus river begins south east of Colossae, flows through the valley to join the Meander River. The Meander flows west to the Aegean Sea at Miletus. The dotted lines show the major roads traversing the valley.