Beacon Hill is known for its scenic ledges overlooking a surrounding salt marsh and the greater Sound and for its unique microclimate ecosystems and rare plant communities.

Beacon Hill, like much of the Metacomet Ridge, is composed of basalt, also called traprock, a volcanic rock.

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

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.

Beacon Hill, open to hiking, picnicking, snowshoeing, bird watching, and other passive pursuits, is isolated from the surrounding suburban areas of Branford and East Haven by salt marsh, riverway, and other wetlands.

The hill is steep, with talus slopes in several locations, and offers scenic vistas of Long Island Sound and protected salt marsh from a number of outlooks.