La Casona is the main edifice of the old Hacienda Santa Rosa. The battle of 1856 was fought around this building, and the military action is described with wonderful displays detailing (in English and Spanish) the old gold-rush route, William Walker's evil imperial plans, and the 20-day-battle breakdown. There are also exhibits on the region's natural history. Two hiking trails leave from behind the museum.
La Casona is located near the park headquarters in the Santa Rosa sector.
