Amarkantak plateau in the Maikal hills marks the origin of the river :

The Narmada River originates from the Amarkantak Plateau, which is part of the Maikal Hills in Madhya Pradesh [2]. Specifically, the river emerges from a small reservoir known as Narmada Kund [3]. From its source, the Narmada flows westward for approximately 1,312 km through a rift valley situated between the Vindhyan and Satpura ranges before emptying into the Gulf of Khambat in the Arabian Sea [2]. Other rivers like the Son and Johila also originate from this plateau [1]. In contrast, the Chambal River rises in the Vindhyan Range near Mhow [4], while the Gandak is a Himalayan river originating on the southern slopes of the Tibetan Highlands. The Narmada is considered the longest west-flowing river in India and is often referred to as the 'Life Line of Madhya Pradesh'.

Sources

1. [2] CONTEMPORARY INDIA-I ,Geography, Class IX . NCERT(Revised ed 2025) > Chapter 3: Drainage > The Narmada Basin > p. 21
2. [3] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 3: The Drainage System of India > The Son River > p. 16
3. [1] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 3: The Drainage System of India > Narmada River > p. 20
4. [4] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 3: The Drainage System of India > The Chambal > p. 14