Smaller communities include stands of Lacey oak (Quercus laceyi), pecan (Carya illinoinensis)-sugarberry (Celtis laevigata) groves, and gramagrass-switchgrass (Panicum virgatum) grasslands, as well as fields of sotol (Dasylirion wheeleri).

The natural vegetation of the property, like much of the Texas Hill Country, has suffered from overgrazing and the introduction of invasive species like exotic King Ranch bluestem (Bothriochloa ischaemum var.

Feral pigs, exotic fallow and axis deer, porcupines, rock squirrels, and ringtailed cats can occasionally be encountered.

The land within the preserve has been inhabited for several thousand years, and a number of Native American artifacts have been found on the property, including human remains.

Eventually becoming the Bar-O Ranch, several parcels of land were subsequently donated by Louise Merrick between 1976 and 1982 to establish the Hill Country State Natural Area.

The picturesque, but intermittent, West Verde Creek runs through the preserve, allowing for swimming and fishing when water levels are high enough.

For herd management purposes, TPWD conducts controlled deer hunting by a limited number of hunters during a few weekends each season.

HCSNA also hosts the annual Bandera 100 km ultramarathon run in January[6] HCSNA urges all visitors to respect the "Leave No Trace" set of wilderness ethics: plan ahead and prepare; travel on marked trails only; always dispose of waste properly; leave behind what you find; never build an open fire; respect wildlife; and be considerate of other visitors.