It governed progressive sects like Brahmans and Arya Samajists. It also governed persons professing other religious beliefs if such was their customary law and if there was no statue governing them.
In fact until the other day, that is until the passing of the Shariat Act, several Mohammedan Communities like the Khojas, the Cutchi Memons, the Borahs and the Halai Memons were governed by Hindu Law in matters of succession and inheritance. On the other side of the picture were undoubted Hindus like the Muir and other non-Brahmin Hindu castes of Malabar Cochin and Travancore who were governed by the Marumakkathayam Law not by the Hindu Law.
The Bunts and some other communities of Canara were governed by the Aliya Santhana Law and not by the Hindu Law. Several agricultural communities in the Punjab were governed by customary law. It is also well known that generally in South India, in matters of marriage etc., it was the customary law rather than the Hindu law that was prevailing. “Thus it is clear that the body personal law known as Hindu Law was neither the personal law of all Hindus nor was it the personal law exclusively of Hindus”.