Short, authentic Jain view:

1. Jain scriptures clearly say

- Bhagwan Neminath (22nd Tirthankar) attained moksha (nirvan) on Mount Girnar. - This is accepted by both Digambar and Shvetambar traditions (e.g. Kalpasutra in Shvetambar; Neminath-charitra and later Digambar texts for Digambar). - So Girnar as a whole is definitely a nirvan kṣetra / siddha kṣetra of Neminath Bhagwan.

1. About the “5th tonk” specifically

- Traditional Jain granths describe Girnar, Sahasavan, Neminath’s diksha place, keval‑jnan place and moksha place, but they do not use the modern tourist-style counting “1st tonk, 2nd tonk, … 5th tonk” in the original Prakrit/Sanskrit āgamas. - The idea that “the highest / last tonk on Girnar is Neminath’s nirvan‑sthal” is strong, continuous Jain tradition, but it is mainly found in later tirth‑māhātmya, pattāvalis, and local Jain pilgrimage descriptions, not in the earliest āgamas with the exact phrase “5th tonk”.

1. So, to your exact question

- If you ask: “Is Girnar mentioned as Neminath’s nirvan‑sthal in Jain scriptures?” → Yes, clearly. - If you ask: “Is the ‘5th tonk’ by this number name explicitly mentioned in early scriptures as nirvan‑sthal?” → No, not in this exact ‘5th tonk’ wording; that numbering is a later way of referring to the topmost spot where Neminath’s nirvan is believed to have occurred.

In simple terms: Scriptures = Girnar is Neminath’s moksha‑bhumi. Tradition / later texts = That moksha‑bhumi is identified with today’s ‘5th tonk’ at the top of Girnar.

You can read more about Girnar and Neminath Bhagwan here: