Huperzia porophila, the rock clubmoss or rock firmoss, grows throughout the Appalachian province of the Eastern United States and central Canada, from Ontario south to Georgia and Alabama.

It is rare east of the Appalachians, being most common in a north–south belt along the western plateau area.

[3] Huperzia porophila grows only on or over rock and requires cool, moist, shaded, acid spots.

It is often confused with the shining firmoss (Huperzia lucidula) whose range it largely shares and which also often grows on rocks.

Unlike H. lucidula, it only grows as individual plants and not as dense colonies.