Some of the hiking trails include steep sections; they can involve as much as 900 feet (270 m) of elevation change.

"[2] Vegetation on the southern and western slopes of the two ridges is predominantly: black sage, chamise and buck brush, with lesser amounts of toyon, hybrid manzanitas, elderberry, gooseberry, chaparral currant, sticky monkeyflower, coffeeberry, coyote bush, poison oak, hollyleaf red berry, deer weed and dozens of other species.

[1] Chamise and Bollinger Creek Loop trails lead to Las Trampas Ridge, east of Bollinger Creek.The ridge offers good views of the Ygnacio, San Ramon and Amador valleys, as well as Mt.

Cows, calves, steers and an occasional free-ranging bull can be encountered on the trails; their grazing keeps the grass short for summer fire safety.

Caution should be exercised with small dogs and children, particularly after sunset with regard to wild animals.

[1] On its eastern border, the park encloses the triangular property of the Eugene O'Neill National Historic Site on all three sides, with access from Las Trampas via hiking trails or from Danville by single-lane road.