You can find an index of all the 31 Days of Encountering Judaism here.
Once upon a time, I would have answered that question with up in heaven, beyond the clouds. I would have answered it that way fairly recently.
But since EfM (Education for Ministry. I go on about that course a fair bit, I should write about it after these 31 Days are done).
Anyway, since EfM and further reading, my understanding of God's kingdom's location has changed.
Jesus in the synoptic Gospels (Matthew, Mark, Luke) said the kingdom of God is near. He meant the fulfillment of God's kingdom being restored on earth, and he meant it in an apocalyptic, end of this Age sense.
In the Jewish tradition, it is up to the people of Israel to be co-creators of God and restore God's kingdom here on earth. In Hebrew, this is known as tikkun olam, healing the world.
Recent Christian thinkers, like Brian MacLaren, have echoed the words of Jesus from the Gospel of John where He declares the kingdom of God is here.
So while two days ago we talked about how the two faiths were once the same, now different; here we see the two faiths coming together in agreement.
In this, we can band together and do something about healing our environment, taking care of the poor and widow, freeing the enslaved, and becoming a peace-natured people.
Hey, I didn't say it would be easy.