Lonar Lake, also known as Lonar crater, is a notified National Geo-heritage Monument saline soda lake located at Lonar in Buldhana district, Maharashtra, India, which was created by a meteor impact during the Pleistocene Epochand it is the only known hyper velocity impact crater in basaltic rock anywhere on Earth.

It was identified in 1823 by a British officer named C.J.E. Alexander. Lonar Crater sits inside the Deccan Plateau—a massive plain of volcanic basalt rock leftover from eruptions some 65 million years ago. Its location in this basalt field suggested to some geologists that it was a volcanic crater. Today, however, Lonar Crater is understood to result from a meteorite impact that occurred between 35,000 and 50,000 years Ago[6]. The lake, which lies in a basalt impact structure, is both saline and alkaline in nature. Geologists, ecologists, archaeologists, naturalists and astronomers have published studies of various aspects of this crater lake ecosystem.Lonar Lake has a mean diameter of 1.2 kilometres (3,900 ft) and is about 137 metres (449 ft) below the crater rim. The meteor crater rim is about 1.8 kilometres (5,900 ft) in diameter.

The circular depression bears a saline water lake in its central portion.The crater’s age is usually estimated to be 52,000 ± 6,000 years (Pleistocene), although a study published in 2010 gives an age of 570,000 ± 47,000 years.

The Smithsonian Institution, the United States Geological Survey, Geological Society of India, the University of Sagar and the Physical Research Laboratory have conducted extensive studies of the site. Biological nitrogen fixation was discovered in this lake in 2007.