It borders Taegwan and Tongch'ang to the north, Unsan and Nyŏngbyŏn to the east, Pakch'ŏn and Unjŏn to the south, and Kusŏng to the west.

The tallest of these is Paegundŏksan (백운덕산, 868 m), but the county's highest point is in the north, at Samgaksan (삼각산, 936 m).

T'aech'ŏn county is divided into 1 ŭp (town), 1 rodongjagu (workers' district) and 21 ri (villages): The year-round annual temperature is 8.5 °C, with a January mean of -10 °C and an August mean of 23.8 °C.

The Ch'ŏngnyŏn P'arwŏn Line of the Korean State Railway passes through the county, on its way between Kusŏng and Kujang.

The construction of the Taechon nuclear power plant (39°55′41″N 125°34′08″E / 39.928°N 125.569°E / 39.928; 125.569) was halted in 1994 in accordance with the U.S.-North Korea Agreed Framework.