The Acirvati was an ancient river flowing through what is now Nepal

Nepal

Nepal , officially the Federal Democratic Republic of Nepal, is a landlocked sovereign state located in South Asia. It is located in the Himalayas and bordered to the north by the People's Republic of China, and to the south, east, and west by the Republic of India...

 and the northern portion of Uttar Pradesh

Uttar Pradesh

Uttar Pradesh abbreviation U.P. , is a state located in the northern part of India. With a population of over 200 million people, it is India's most populous state, as well as the world's most populous sub-national entity...

. It has been identified with the modern Rapti

West Rapti River

Not to be confused with the East Rapti in Chitwan Valley some to the east, this Rapti drains Rapti Zone in Mid-Western Region, Nepal, then Awadh and Purvanchal regions of Uttar Pradesh state, India before joining the Ghaghara a major left bank tributary of the Ganges.The West Rapti is notable for...

.

The Aciravati was also known as the Ajiravati or the Airavati. The Chinese pilgrim Yuan Chwang

Xuanzang

Xuanzang was a famous Chinese Buddhist monk, scholar, traveler, and translator who described the interaction between China and India in the early Tang period...

 knew it as A-chi-lo. Jain texts mention it as Eravai.

The ancient city of Sravasti

Sravasti

Śrāvastī or Sāvatthī , a city of ancient India, was one of the six largest cities in India during Gautama Buddha's lifetime. The city was located in the fertile Gangetic plains in the present day Gonda District of Uttar Pradesh near Balrampur some 120 km north of Lucknow...

, once capital of Kosala Kingdom

Kosala Kingdom

Kosala Proper or Uttara Kosala is the kingdom of the celebrated personality of Treta Yuga, Raghava Rama. Ayodhya was its capital, presently in Faizabad district, Uttar Pradesh. Rama's sons Lava and Kusha inherited parts of this kingdom. Lava ruled from the city called Sravasti and Kusa from the...

, stood on the western bank of the Aciravati. It was a tributary of the Sarayu

Sarayu

The Sarayu is a river that flows through the Indian state of Uttar Pradesh. This river is of ancient significance, finding mentions in the Vedas and the Ramayana. The Sarayu forms at the confluence of the Karnali and Mahakali in Bahraich District...

. It was one of the five great rivers that constituted the Ganges group of rivers. It was one of the sacred rivers of the Buddhist midland.