How can God be omnipresent and not in Hell?

Hell is not a place, it's a state (of spiritual separation from God).

I agree with Chris here when He said Psalm 139, "If I go down to hell, You are there also." God is there with us. ...

Hell is a real place. It is not mere unconsciousness. It is not temporal. It is eternal torment. Perhaps that is why Jesus spoke more of hell than heaven and spent so much time warning people not to go there. After all, if people just stopped existing, why warn them? If it was temporal, they'd get out in a while. But if it were eternal and conscious, then the warning is strong.

The teaching that there is an eternal hell in which hordes of mankind will suffer eternal punishment can be a difficult doctrine to accept. We hear so much about God's infinite love and how He desires that all men be saved (1 Tim. 2:4). However, those who develop their theologies based upon the "gentle" side of God do so with an incomplete picture. Not only is God loving (1 John 4:8-10), gracious (Exo. 33:19; 1 Pet. 2:3), and merciful (Exodus 34:6; Psalm 67:1; James 5:11), but He is also holy (Isaiah 6:3; Rev. 4:8), just ( Neh. 9:32-33; 2 Thess. 1:6), and hates sin (Psalm 5:5-6; Hab. 1:13). God punishes the sinner (Jer. 50:31; Ez. 44:12; Matt. 25:46; 2 Thess. 1:9; 2 Pet. 2:9; Heb. 10:29).

The Bible teaches that there is a fiery hell, a place that Jesus warned people about.

Hell is a place of torment. The people there have been cut off from God's presence for eternity and they cannot feel him even if he is there.

Silly goose, God is in hell too.

not everyone says God is omnipresent

His awareness is certainly everywhere

but God is different to creation... not bound in space-time

I guess he could, but he prefers to go to Bahamas.