Where is heaven and where is hell?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

We ask Allah, the Great and Almighty, to grant all of us Paradise and to save us from the Hell-fire.
In fact, there is disagreement among scholars concerning the place of the Hell-Fire. Some say it is in the beneath the Earth; others say in the Sky. A third group gives no answer since there is not sound Hadith in this concern.
Imam al-Suyooti (may Allah's mercy be upon) says: 'One has to avoid speaking about the place of the Hell-Fire, and only Allah knows its place, since there is no proved evidence to depend on.' And this the last opinion is the dominant one.
As for Paradise, Allah says: {And indeed he (Muhammad SAW) saw him [Jibrael (Gabriel)] at a second descent (i.e. another time). Near Sidrat-ul-Muntaha [lote-tree of the utmost boundary (beyond which none can pass)], Near it is the Paradise of Abode.} [53:13, 14, 15]
Imam al-Qurtubi (may Allah's mercy be upon him) stated in his explanation of the Qur'an: his verse indicates to the place of Paradise and that it is near the lote-tree of the utmost boundary (beyond which none can pass).
Also, al-Hassan, al-Basri supported the above stated opinion, where the righteous will reside.
Allah knows best.