The Rig Veda is recognised as the oldest literature by mankind. It is one of the sources of Sanatana Dharma. It, as in other Vedas, contains four portions. Samhita,Hymns;Brahmanas,Procedures for Rites; Aranyaka and Upanishads, containing Ontology and Philosophy. Earlier evidence suggesting it having been composed in Northern,North Western part of India is being revisited on the basis of evidence found in Russia that the Rig Veda could have been composed in the Arctic.
The Rig Veda is organized as Mandala (books), sukta (hymns) and riks (prayers). There are total of 10 mandalas, 1028 hymns and 10552 riks.
The text is layered consisting of the Samhita, Brahmanas, Aranyakas and Upanishads.[note 3] The Rigveda Samhita is the core text, and is a collection of 10 books (maṇḍalas) with 1,028 hymns (sūktas) in about 10,600 verses (called ṛc, eponymous of the name Rigveda). In the eight books – Books 2 through 9 – that were composed the earliest, the hymns predominantly discuss cosmology, rites, rituals and praise deities.The more recent books (Books 1 and 10) in part also deal with philosophical or speculative questions,virtues such as dāna (charity) in society, questions about the origin of the universe and the nature of the divine, and other metaphysical issues in their hymns.
The main contributors were Angiras, Kanva, Vasishtha, and Vishvamitra. Among the other celebrated authors are Atri, Bhrigu, Kashyapa, Gritsamada, Agastya, Bharadvaja, as well as female sages Lopamudra and Ghosha. In a few cases, more than one rishi is given, signifying lack of certainty. Source..https://en.m.wikipedia.org/wiki/Rigveda
Of these twelve Rishis who have composed the Rigveda, Lopamudra and Ghosha were women ,Rishikas.