In Hinduism, a Brahmarshi (Sanskrit brahmarṣi, a tatpurusha compound of brahma and ṛṣi) is a member of the highest class of Rishis ("seers" or "sages"). A Brahmarshi is a sage who has attained enlightenment (Kaivalya or Moksha) and became a Jivanmukta by completely understanding the meaning of Brahman and has attained the highest divine knowledge, infinite knowledge (omniscience) and self knowledge called Brahmajnana. When a Brahmarshi dies he attains Paramukti and frees himself from Samsara, the cycle of birth and death.
Bhrigu, Angiras, Atri, Vishwamitra, Kashyapa, Vasishta, and Shandilya are the seven brahmarshis. But there is another list of Saptarishi also who are also Gotra-pravartakas, i.e.,founders of Brahamanical clans, and this second list appeared somewhat later, but belongs to ancient period.
All the hymns of third mandala of the Rig Veda, including the Gayatri mantra, are ascribed to Vishwamitra, who is mentioned as the son of Gaadhi. According to Puranic stories, Vishwamitra was the only brahmarshi who rose to the position out of pure tapas. Originally belonging to the kshatriya, he rose by pure merit to a Brahmarishi. Vishwamitra is also referred to as Kaushika, because he attained Brahmajnana on the banks of the river Koshi.
Parasurama and Jamadagni have also been credited the title of Brahmarishi by Bhishma as in Mahabharata.
The Period of the Manusmriti
Brahmarshi-desha, 'the country of the holy sages,' includes the territories of the Kurus, Matsyas, Panchalas and Surasenas (i.e. the eastern half of the State of Patiala and of the Delhi division of the Punjab, the Alwar State and adjacent territory in Rajputana, the region which lies between the Ganges and the Jumna, and the Mathura District in the United Provinces).