Mark 1:21–28 (ESV)
21 And they went into Capernaum, and immediately on the Sabbath he entered the synagogue and was teaching. 22 And they were astonished at his teaching, for he taught them as one who had authority, and not as the scribes. 23 And immediately there was in their synagogue a man with an unclean spirit. And he cried out, 24 “What have you to do with us, Jesus of Nazareth? Have you come to destroy us? I know who you are—the Holy One of God.” 25 But Jesus rebuked him, saying, “Be silent, and come out of him!” 26 And the unclean spirit, convulsing him and crying out with a loud voice, came out of him. 27 And they were all amazed, so that they questioned among themselves, saying, “What is this? A new teaching with authority! He commands even the unclean spirits, and they obey him.” 28 And at once his fame spread everywhere throughout all the surrounding region of Galilee.
Capernaum is the place where Jesus moved after being in Nazareth, his home town. This was sort of the headquarters of his ministry. Capernaum was a relatively blue collar town with the most common industries being fishing, farming, crafting, and common trading. The location on the Sea of Galilee and it's positioning on a popular trade route led it to being a place of economic prosperity.
There was a Roman presence there, as in all of the Jewish world at this time, but since Capernaum is a border town it was likely a heavier Roman presence than other places. Yet, the relations between the Romans and the Jews seemed to be peaceable. In Luke 7 we learn that the Roman centurion actually helped build the Jewish synagogue there. Yet the presence of the Roman centurion and his men along with the tax collectors would be a pervading reminder of the Roman occupation. An occupation that the Jews believed the coming Messiah would overthrow and return Israel to an independent state.
The city was mostly populated by Jews but being on a common trade route likely experienced a good bit diversity. All in all, it was kind of a strange place for Jesus to make the base of his ministry operations. The center of the Jewish religious world was in Jerusalem, where the temple rested. Jerusalem isn't shown on the map below but it is located south of Samaria.
