Thane is a district in northern Maharashtra. As of 2011, it is the most populated district in India. The headquarters of the district is the city of Thane. Other major cities in the district are Navi Mumbai (formerly New Mumbai), Kalyan-Dombivli, Mira-Bhayander, Bhiwandi, Ulhasnagar, Ambarnath, Kulgaon-Badlapur, Dahanu, Shahapur, Wada and Vasai-Virar. This is the third-most industrialised district in Maharashtra.
The district is surrounded by Pune and Ahmadnagar on the east, Nashik on the east and northeast, Valsad District of Gujarat state and Union Territory of Dadra and Nagar Haveli on the north. The Arabian Sea forms the western boundary, while it is bounded by Mumbai City District and Mumbai Suburban District on the southwest and Raigad District on the south.
Thane has 15 talukas namely Thane, Kalyan, Murbad, Bhiwandi, Shahapur, Vasai, Ulhasnagar, Ambarnath, Dahanu, Palghar, Talasari, Jawhar, Mokhada, Wada and Vikramgad. Thane is presently the only district in India which comprises seven municipal corporations namely Mira-Bhayandar, Thane, Navi Mumbai, Kalyan-Dombivali, Ulhasnagar, Bhiwandi and Vasai-Virar.
There are 24 Vidhan Sabha constituencies in Thane district. Dahanu (ST), Vikramgad (ST), Palghar (ST), Boisar (ST), Nalasopara and Vasai constituencies are part of Palghar Lok Sabha constituency. Bhivandi Rural (ST), Shahapur (ST), Bhivandi West, Bhivandi East, Kalyan West and Murbad constituencies are part of Bhiwandi Lok Sabha constituency. Ambarnath (SC), Ulhasnagar, Kalyan East, Dombivali, Kalyan Rural and Mumbra-Kalwa constituencies are part of Kalyan Lok Sabha constituency. Mira Bhayandar, Ovala-Majiwada, Kopri-Pachpakhadi, Airoli, Thane and Belapur constituencies are part of Thane Lok Sabha constituency.