How Are We to Understand Jonah: As Historical?

How to interpret and understand Jonah is troublesome. Many come to its four chapters wanting to believe its teachings, but struggle with its content. Obviously this is rooted in our post-englightened minds where all miracles are suspect and all ancient documents are treated as mythical. Therefore, when coming to the book of Jonah, not only is it helpful to consider that the book is a form of Hebrew midrash (see that here), we must really begin, I believe, with the conviction that the book of Jonah records historic events.

Here is why I believe Jonah is a historic books and ought to be interpretted as such:

1. Jonah begins (Jonah 1:1) with the same verb common in narratives. The King James Version often translates this as it came to pass and is common in narratives. See, for example, Joshua, Judges, Ruth, 1-2 Samuel, Esther, and Nehemiah.
2.  Jonah was a real, historical prophet. We know this from 2 Kings 14:25 which says, [Jeroboam II] restored the border of Israel from the entrance of Hamath as far as the Sea of the Arabah, according to the word of the Lord, the God of Israel, which He spoke through His servant Jonah the son of Amittai, the prophet, who was of Gath-hepher.
3. The places recorded in Jonah are actual locations. Ninevah, Tarshish, and Joppa.
4. Jesus considered the prophet and the events recorded as historical. Consider the following passages:
1. Matthew 12:38-41 – Then some of the scribes and Pharisees said to Him, “Teacher, we want to see a sign from You.” But He answered and said to them, “An evil and adulterous generation craves for a sign; and yet no sign will be given to it but the sign of Jonah the prophet; for just as Jonah was three days and three nights in the belly of the sea monster, so will the Son of Man be three days and three nights in the heart of the earth. The men of Nineveh will stand up with this generation at the judgment, and will condemn it because they repented at the preaching of Jonah; and behold, something greater than Jonah is here.
2. Matthew 16:4 - An evil and adulterous generation seeks after a sign; and a sign will not be given it, except the sign of Jonah.” And He left them and went away.
3. Luke 11:29-30 - As the crowds were increasing, He began to say, “This generation is a wicked generation; it seeks for a sign, and yet no sign will be given to it but the sign of Jonah. For just as Jonah became a sign to the Ninevites, so will the Son of Man be to this generation.
5. The authors of 3 Maccabees and Tobit as well as the first century Jewish historian, Josephus, all regarded Jonah was historical.
1. 3 Maccabees 6:8 - And Jonah, wasting away in the belly of a huge, sea-born monster, you, Father, watched over and restored unharmed to all his family.  
2. Tobit 14:4 -  Go into Media my son, for I surely believe those things which Jonas the prophet spake of Nineve, that it shall be overthrown; and that for a time peace shall rather be in Media; and that our brethren shall lie scattered in the earth from that good land: and Jerusalem shall be desolate, and the house of God in it shall be burned, and shall be desolate for a time.
3. Tobit 14:8 - And now, my son, depart out of Nineve, because that those things which the prophet Jonas spake shall surely come to pass.  
4. Josephus Book9, Chapter 10   - Now I cannot but think it necessary for me, who have promised to give an accurate account of our affairs, to describe the actions of this prophet, so far as I have found them written down in the Hebrew books. Jonah had been commanded by God to go to the kingdom of Nineveh; and when he was there, to publish it in that city, how it should lose the dominion it had over the nations. But he went not, out of fear; nay, he ran away from God to the city of Joppa, and finding a ship there, he went into it, and sailed to Tarsus, in Cilicia (19) and upon the rise of a most terrible storm, which was so great that the ship was in danger of sinking, the mariners, the master, and the pilot himself, made prayers and vows, in case they escaped the sea: but Jonah lay still and covered [in the ship,] without imitating any thing that the others did; but as the waves grew greater, and the sea became more violent by the winds, they suspected, as is usual in such cases, that some one of the persons that sailed with them was the occasion of this storm, and agreed to discover by lot which of them it was. When they had cast lots, (20) the lot fell upon the prophet; and when they asked him whence he came, and what he had done? he replied, that he was a Hebrew by nation, and a prophet of Almighty God; and he persuaded them to cast him into the sea, if they would escape the danger they were in, for that he was the occasion of the storm which was upon them. Now at the first they dare not do so, as esteeming it a wicked thing to cast a man who was a stranger, and who had committed his life to them, into such manifest perdition; but at last, when their misfortune overbore them, and the ship was just going to be drowned, and when they were animated to do it by the prophet himself, and by the fear concerning their own safety, they cast him into the sea; upon which the sea became calm. It is also reported that Jonah was swallowed down by a whale, and that when he had been there three days, and as many nights, he was vomited out upon the Euxine Sea, and this alive, and without any hurt upon his body; and there, on his prayer to God, he obtained pardon for his sins, and went to the city Nineveh, where he stood so as to be heard, and preached, that in a very little time they should lose the dominion of Asia. And when he had published this, he returned. Now I have given this account about him as I found it written [in our books.]
6. The story teaches truths about God’s sovereignty & providence over creation that make no sense unless the events actually took place.
1. 1:4, 15 – Sovereignty over the storm.
2. 1:17 – Sovereignty over the fish.
3.  4:6 – Sovereignty over the plant.
4.  4:7 – Sovereignty over the worm.
5.  4:8 – Sovereignty over the east wind
6.  Sovereignty of God over the salvation of man. God has determined to save Ninevah & saw to it that it was accomplished.
7.  Historic Circumstances make Jonah make sense.
1. Israel, the northern state, was in the midst of political peace. 
2. Assyria was weak, engaged in conflicts w/ the Arameans.
3. There was a widespread famine, numerous revolves throughout the Assyrian empire, an a strange solar eclipse.
4.  Such a stack of events give credence of the Ninevites responding so willingly to the message of Jonah.
8. Rejecting Jonah's historicity has dangerous implications. Although there is certainly some allegorical meaning in the book (could the swallowing of the fish correspond to Israel's Babylonian Captivity, for example), to outright reject the book as history is dangerous. The slippery slope argument is valid. If first Jonah, then what? Are we to interpret the rest of Scripture we do not like as myth?

For more:
How Are We to Understand Jonah: As Midrash?
Holman Dictionary on Jonah
Bibledex on Jonah
VeggieTales and Jonah