Don't think the Marvel ones ever said where it was at. The new IDW one is in Illinois.

I just read the first 20 Marvels, I'm pretty sure Springfield was in Vermont. I think it was compromised as a secret Cobra base, so maybe they moved it to the mid-west. Seems a more logical to do that anyway; central location makes it easier to launch a full on attack on the US if Cobra Commander so desired.

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The United States will conquer Terrorism with the help of God and a few Marines.

Some people, when trying to avoid thinking about those things that cause them pain, turn to drink, or perhaps food, or drugs... I turn not to any of those... I collect action figures, turning my mind to the hunt, so that I might find a mote of peace... Over the years, I've found that alcoholism is much more socially acceptable by far.