Sonagachi, translated as Golden Tree, is the largest red light district in Kolkata (Calcutta), India. It is an area with
several hundred multi-story brothels and some 10,000 sex workers. Sonagachi is located in North-Kolkata near the intersection of Chittaranjan Avenue, Sova Bazar and Beadon Street, just north of the Marble Palace.

History
The area was used by the Bengali Babus for maintaining concubines and mistresses in the 1700s and 1800s. Several mansions in this district have their roots in history in the early days of British Raj. Legends say that even the famous courtesans and patrons of Paris knew of the fame of the Golden district of Kolkata.

Today, several NGOs and government organizations operate here for the prevention of sexually transmitted diseases [STD] including AIDS. The Sonagachi project is a prostitute's cooperative that operates in the area and empowers sex workers to insist on condom use and to stand up against abuse. The Durbar Mahila Samanwaya Committee (DMSC) runs the Sonagachi project and several similar projects in West Bengal, organizing some 65,000 prostitutes and their children. The DMSC hosted India's first national convention of sex workers on November 14th, 1997 in Kolkata, entitled 'Sex Work is Real Work: We Demand Workers Rights'. The organization lobbies for the recognition of sex workers' rights and full legalization, runs literacy and vocational programs, and provides micro loans.