Unquestionably the park’s single most popular destination, the Mirador de Selkirk (Selkirk’s Lookout) is a stiff hike that starts at Subida El Castillo, at the south end of San Juan’s plaza. Over a distance of 2,700 meters, it gains 565 meters in altitude—an average grade of nearly 21 percent. The initial segment passes through a badly eroded area that quickly becomes covered with blackberry vines and nonnative scrub before finally entering a dense native forest with a verdant undergrowth of ferns—some the size of trees. This is a designated nature trail, and Conaf’s inexpensive booklet Sendero Interpretativo Mirador Alejandro Selkirk describes the native and nonnative plants and wildlife and explains what environmental damage the area has suffered.

From a saddle on the ridge between the two sides of the island, the hiker’s reward is a series of views from Bahía Cumberland and San Juan on the north to the airfield to Isla Santa Clara on the south. On the saddle itself, two plaques honor Selkirk’s memory. Royal Navy officers placed the first, cast by John Child & Son of Valparaíso, which says:

In memory of Alexander Selkirk, Mariner, a native of Largo, in the county of Fife, Scotland, who lived on this island in complete solitude for four years and four months.

He was landed from the Cinque Ports galley, 96 tons, 16 guns, A.D. 1704 and was taken off in the Duke, privateer, 12th Feb., 1709.

He died lieutenant of HMS Weymouth, A.D. 1723, aged 47 years.

This tablet is erected near Selkirk’s lookout, by Commodore Powell and the officers of HMS Topaze, A.D. 1868.

The second, placed nearby by a Scottish relative, reads:

Tablet placed here by Allan Jardine of Largo, Fife, Scotland, direct descendant of Alexander Selkirk’s brother David. Remembrance ’Till a’ the seas gang dry and the rocks melt in the sun.’ January 1983.

From the saddle, where wind and fog can make the weather far cooler than at sea level, the trail descends through densely vegetated Sector Villagra before emerging onto the desert side of the island; it’s about 10 kilometers farther to the airfield on a path that, for most of its length, is wide enough for a Hummer. Villagra has a ranger station and campground where islanders gather for the summer rodeo, in early February.

Through hikers should carry water, as the only reliable sources en route are a conspicuous pipe where the trail crosses Estero El Castillo (San Juan’s water supply) and begins to switchback toward Selkirk’s lookout, and a spring that drops over a rock outcrop just west of the Villagra turnoff.