Thane District forms a part of North Konkan Region. Which lies between the Sahyadri hills in the east and the Arabian Sea in the West. It has coastal line of about 113 Kms. It lies Between 18°42′ and 20°20′ North latitudes and 72°45′ to 73°48′ East longitudes in eastern part of the state Its East-West spread is maximum at the South which is about 100 Kms. The North-south length is approximately 140 Kms. District head quarter Thane is about 25 Kms from the international airport and 35 Kms from the main down town of Mumbai City.
According to the 2011 census, the area of divided district is 4214 sq. Km and it is 1.37% of the total area of the state.If the area is considered, then the district is 33rd in the state. Shahapur Taluka has the highest area of 7 talukas in the district and is 1629 sq km. (38.66 per cent) and the smallest Ulhasnagar taluka 13 sq.km. (0.31 percent) of the area. The two talukas Thane and Ulhasnagar are completely urban in the district. Alongwith these two talukas, Kalyan, Bhiwandi and Ambernath talukas are comparatively developed.
Pune and Ahmednagar districts are in the east of the district. Nashik district is on the north east and Palghar district is to the north. The Arabian Sea is spread on the west side of this district, and the districts of Mumbai Suburban and Raigad are on the southern side.
The district is divided into three parts on the basis of its topography.
Sahyadri range, which has the eastern boundary, has a boundary line on the Sahyadri boundary. Also, small mountain ranges are divided spaced. The mountain ranges in the east are high-altitude and gradually decreases in the west. In the central part of the district there are also small mountain ranges.
Yeoor and Mama Bhanja Hills in Thane district is a cool place to live.
There are two important rivers in Varanasi and Ulhas in Thane district. Vaitarna river originates from Trimbak base in north-east of Nashik district and swept it southwards into Shahapur taluka of Thane district and then flows through the talukas of Wada, Palghar and get Arabian sea in Vaitarna Bay in Navghar on the south side of Palghar. Tansa river originates from Ghatmath in Shahapur taluka and later it meets the Vaitarna river at Chiman in Vasai taluka. On the right side of the Vaitarna river, the tributaries of Pinjal, Dherja and Surya are available and on the left side the river Tansa gets. Ulhas river originates from Bhormatha and goes to Karjat taluka from Raigad district and further to Vasai Bay. The Ulhas river has three tributaries, the Barvi river originates from Ghatmathi in Murbad taluka. Later it gets Ulhas river in the village of Aapnath taluka. Origin of the river Bhatsa, through Ghatmath in Shahapur taluka, it comes near the village of Vadwali in Kalyan taluka and meets Ulhas River. The Kalu river of the Bhatsa river is the main tributary, and it gets through Bhatsa river near Samodh village in Kalyan taluka, through Ghatmath of Shahapur taluka. The tributaries of Barvi and Bhatsa come with Ulhas river towards its right side. 25 km inside the shoreline of Vertran Creek. The interstate part of the Ulhas River and 40 km from Kalyan is suitable for water transport.
According to the type of land, the surface of the ground is mainly divided into two parts.
The climate of the district is distinctly different on the coastal plains and on the eastern slopes. Being fully tropical, the climate on the coast, the coastal strip including Thane, Vasai, Palghar and Dahanu tahsils is very humid and warm. On the other hand, the climate on the eastern slopes and in the plains at the foot of the slopes is comparatively less humid. However, variation in temperature in the eastern region is more than that on the coastal strip. The maximum temperature lies between 28.0 to 35.2 centigrade and the minimum temperature lies between 16.3 to 26.5 centigrade.
The district gets assured rainfall of 2000 to 4000 m.m. from the South-West mansoons during the months June to September. Generally highest rainfall is recorded in the month of July. It is considerably more inland than on the coast. It is also less towards the North more inland than on the coast. It is also less towards the North than towards the South.