Ratngiri (Marathi: ) is a port city on the Arabian Sea coast in Ratnagiri district in the southwestern part of Maharashtra, India. The district is a part of Konkan.
The Sahyadri mountains border Ratnagiri to the east. Heavy rainfall results in highly eroded landscape in the coastal region, but fertile alluvial valleys in the region produce abundant rice, coconuts, cashew nuts, and fruits, "Hpus" (Alphonso) mangoes being one of the main fruits. Fishing is an important industry in Ratnagiri.
A few illustrious Indians, including "Lokmnya" Bal Gangadhar Tilak, a prime leader in the nation's freedom movement in the British Raj days; Bharat Ratna "Maharshi" Dhondo Keshav Karve, a social reformer and educationist; and Wrangler Raghunath Purushottam Paranjpe, a mathematician and educationist, were born in Ratnagiri or its vicinity.
Ratnagiri has also been featured in Amitav Ghosh's novel, 'The Glass Palace.' The Jaitapur Nuclear Power Project is located in the district.