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"), especially those credited with the composition of the hymns collected in the Rigveda. 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 brahmarishis. 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 is ascribed to Vishwamitra who is mentioned as son of Gaadhi, including the Gayatri mantra. According to Puranic stories, Vishwamitra was the only brahmarishi 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.
Parsurama has also been credited the title of Brahmarshi by Bheeshma in Mahabharata .
Brahmarshi-desha, 'the county 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 Muttra District in the United Provinces).