The mountain consists of an upper summit ridge with two distinct peaks and a lower plateau and ledge that hangs just above the center of Farmington.

The historic Hill-Stead Museum, known for its French Impressionist masterpieces, architecture, and stately grounds[4] is located on the northern part of the ridgeline.

The southern half of the mountain is made up of largely wooded cliffs; the Farmington Reservoir is nestled between the ridge high point and the edge of the lower plateau.

[3] Farmington Mountain, like much of the Metacomet Ridge, is composed of basalt, also called traprock, a volcanic rock.

The mountain formed near the end of the Triassic Period with the rifting apart of the North American continent from Africa and Eurasia.

Subsequent faulting and earthquake activity tilted the strata, creating the cliffs and ridgeline of Farmington Mountain.

Hot, dry upper slopes, cool, moist ravines, and mineral-rich ledges of basalt talus produce a combination of microclimate ecosystems on the mountain that support plant and animal species uncommon in greater Connecticut.

The trust has secured a number of easements on the lower slopes of the mountain and adjacent parts of Metacomet Ridge.