Samos is a Greek island in the Aegean Sea that is only 1 mi. [1.6 km] from the western shore of Turkey separated from it by the Mycale Strait.
It was home of Pythagoras, the famous mathematician and the philosopher Epicurus. But for the ancients it was the place associated with Hera, the wife of Zeus whose cult was celebrated at the temple called the "Heraion of Samos."
Acts 20: 15 says: "And sailing from there [Mitylene], we arrived the following day opposite Chios; and the next day we crossed over to Samos; and the day following we came to Miletus." (NASB)
The route that Paul's vessel took from Chios to Miletus is carefully examined by Dr. Mark Wilson at the beginning of his article "The Ephesian elders come to Miletus: An Annaliste reading of Acts 20:15-18a." He argues that the vessel that Paul was on sailed through the narrow strait between Samos and Turkey—the "Mycale Strait"— and possible landed at the chief city of Samos—Pythagoras or at Trogilium closer to the (present) Turkish mainland.
Please note that the coastline north of Mileus on the above map is not correct for Paul's day—please see more accurately the map below from Wikipedia:
From: Eric Gaba, Wikimedia Commons user Sting [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
WILSON, M.. The Ephesian elders come to Miletus: An Annaliste reading of Acts 20:15–18a. Verbum et Ecclesia, North America, 34, sep. 2013. Available at: <http://www.ve.org.za/index.php/VE/article/view/744/1751>. Date accessed: 18 Oct. 2013.