Name the peninsula in Europe that had greek colonies that were the farthest away from mainland greece

The correct answer is - Iberian Peninsula.

The Ancient Greeks were constantly traveling and trading across the Mediterranean and the surrounding seas. As they were doing that, they gradually made their own little colonies, all of which on the coastline. They made small colonies in what is now Turkey, in Crimea and most of the coastline of the Black Sea, Italy, Sicily, France, North Africa, and the Iberian Peninsula. They made two colonies on the Iberian Peninsula, one of which was near modern day Valencia, while the other came out on the Atlantic Ocean, near the modern day border between Spain and Portugal, which was actually the colony that was also the furthest away form the Greek city-states in Greece.