It is bounded to the north by Ŭiju, to the east by Chŏnma, to the south by Yŏmju and Tongrim, and to the west by Ryongchŏn and the large city of Sinŭiju.

The land of Phihyŏn is generally flat in the west, rolling in the center, and rises to the low Munsu Mountains in the east.

Phihyŏn is divided into 1 ŭp (town), 2 rodongjagu (workers' districts) and 21 ri (villages): The year-round average temperature is 8.5 °C, dipping to a January mean of -9.5 °C and rising to 23.6 °C in August.

Crops raised on that cultivated land include rice, maize, soybeans, and sweet potatoes.

The Phyŏngŭi (Pyŏngyang-Sinŭiju) and Paengma (Yŏmju-South Sinŭiju) lines of the Korean State Railway pass through the county.