Sathyamangalam is situated on the southern side of the Western Ghats, which extends towards the east from the Nilgiri mountains. The town lies close to the border of the adjoining state of Karnataka. The general topography of this town is not flat and the town is generally covered by the sloping lands. The river Bhavani flows at the center of the town from west to east. Agricultural wet lands are predominant on both sides of the river and dry lands are predominant in the northern side of the town.
Sathyamangalam is a medium-sized town with an agricultural linter land on all sides. The rate of growth is low, because the northern side is surrounded by reserved forests. Poor industrial activities are also one of the reasons for slow growth rate of urban development. Sathyamangalam Municipality's area in 29.24 km, comprising four revenue villages. Only 10.46% of the municipal area is developed as urban area and the remaining 89.54% remains undeveloped agricultural land.
According to 2011 census, Sathyamangalam had a population of 37,816 with a sex-ratio of 1,006 females for every 1,000 males, much above the national average of 929. A total of 3,382 were under the age of six, constituting 1,737 males and 1,645 females. Scheduled Castes and Scheduled Tribes accounted for 10.38% and .74% of the population respectively. The average literacy of the town was 72.02%, compared to the national average of 72.99%. The town had a total of 11148 households. There were a total of 17,451 workers, comprising 1,094 cultivators, 1,882 main agricultural labourers, 741 in house hold industries, 11,272 other workers, 2,462 marginal workers, 26 marginal cultivators, 430 marginal agricultural labourers, 136 marginal workers in household industries and 1,870 other marginal workers. As per the religious census of 2011, Sathyamangalam had 86.3% Hindus, 10.2% Muslims, 3.4% Christians and 0.1% others.
Sathyamangalam is the headquarters for Sathyamangalam taluk in Erode District. The town was upgraded to a third grade municipality from the status of town panchayat in 1970 and subsequently as a second grade Municipality in 1977. It was elevated to a first grade municipality in 1998.
The town is situated at a distance of 65 km from district headquarters Erode, connected through State Highway 15 via Gobichettipalayam. The Coimbatore-Bangalore National Highway (NH 209) passes through this town. It is well connected by buses from nearby towns and cities with frequent buses available to/from Coimbatore, Erode, Gobichettipalayam and Mysore. The nearest railway station is Erode Junction (63 km). The Erode-Chamrajnagar railway line scheme was proposed in 1915 via Gobichettipalayam, Sathyamangalam. The British conducted surveys in 1922, 1936 and 1942 and survey stones were also laid for the proposed railway line. But after Independence the scheme did not take off and was rejected later amid concerns about destruction of forests and wildlife. The nearest airport is Coimbatore International Airport, which is 65 km by road, which has regular flights to New Delhi, Kolkata, Mumbai, Ahmedabad, Bangalore, Kozhikode, Chennai, Hyderabad, Pune, Sharjah and Singapore.
Sathyamanagalam assembly constituency was merged with Bhavani Sagar as a part of delimitation by the Election Commission of India. It was a part of the Gobichettipalayam parliamentary constituency until 2010 before being merged with Nilgiris.Bhavanisagar dam
Bhavanisagar dam is located on the Bhavani River 16 km (9.9 mi) west to Sathyamangalam. The dam feeds the Lower Bhavani Project Canal and is the second largest dam in Tamil Nadu.Bannari Amman Temple
Bannari Amman temple is one of the famous Amman temples in Tamil nadu and it is located in Bannari on NH 209 near Sathyamangalam. Kundam Festival is celebrated in the Tamil month of Panguni (March - April). This is the most famous annual festival, lakhs of devotees from different directions throng the temple in this month which is marked by festivity and gaiety.Reserve forests
A portion of the Sathyamangalam forests was declared as a wildlife sanctuary in 2008 and as a tiger reserve in 2013. Sathyamangalam was declared as reserve forest under the Wildlife Protection Act, 1973. It is contiguous with the Biligirirangan Temple Wildlife Sanctuary to the north in neighboring Chamarajanagar district of Karnataka, and together forms a vital corridor for elephant movements. The 2009 wildlife survey enumerated 10 Bengal tigers, 866 Indian elephants, 672 gaurs, and 27 leopards. The survey party observed four additional species of horned antelope including 2,348 spotted deer, 1,068 blackbuck, 304 sambar deer, 77 barking deer and four-horned antelope, 843 wild boar, 43 sloth bear and 15 striped hyenas. Herds of the famous feral buffaloes can also be spotted in places near the Moyar river.
The Battle of Sittimungulum(variant spellings include Sattiamungulum, Sathinungulum) was a series of battles and skirmishes fought between 13 and 15 September 1790, during the Third Anglo-Mysore War, in and near the town now known as Sathyamangalam in the southern part of the Sultanate of Mysore. Forces of Mysore's ruler Tipu Sultan very nearly overwhelmed a British East India Company force under the command of Captain John Floyd.