Jannah is located close to the Sidrat-ul-Muntaha. In the Qur’aan Majeed, Allah Ta‘ala says:

عِنۡدَ سِدۡرَۃِ الۡمُنۡتَہٰی ﴿۱۴﴾ عِنۡدَہَا جَنَّۃُ الۡمَاۡوٰی ﴿ؕ۱۵﴾

At Sidrat-ul-Muntaha, near it is Jannat-ul-Ma’waa (the abode of Jannah). (Surah Najm v. 14-15)

It is reported in the narration of Hazrat Abu Sa’eed Khudri (radhiyallahu ‘anhu) that after performing salaah in Bayt-ul-Ma’moor, Rasulullah (sallallahu ‘alaihi wasallam) was raised to the Sidrat-ul-Muntaha. Thereafter, Rasulullah (sallallahu ‘alaihi wasallam) was raised to Jannah, and after his visit to Jannah, Jahannum was presented before him. In other words, the horrors of Jahannum were laid bare before him.