In north India, as per politicians, three major pilgrimage sites are important. The first is Ayodhya, where Ram was born and the kingdom of Ram was established. The second is Mathura where Krishna was born. The third is Kashi, with which Shiva is associated. Ram, Krishna and Shiva form the foundations of modern Hindu practices. With this, one gets the feeling that Hindu gods privilege the Gangetic plain. 

The early Hindu scriptures were restricted to North India. There is reference to Punjab and Haryana in the Rigveda. The Upanishads refer to the wider Gangetic plain. The Mahabharata refers to Bengal and Odisha. Ramayana  speaks of a more southern movement. By the Puranic period, we get more familiar with river systems, like the Narmada and Godavari, indicating a southward movement. Tamil scriptures, of course, talk of Kaveri. The Himalayan region gets increasingly connected with Shiva and many forms of Shakti whose shrines are found atop mountains and in caves.