Morro de Castelo Branco: the Volcanic Dome With Natural Pools at Its Feet

Few hills give their name to an entire parish. Morro de Castelo Branco did exactly that — and still offers, at its base, one of the most peculiar natural pools on the entire island of Faial.

A dome of lava too thick to flow

Linked to Faial’s central Caldeira volcano, Morro de Castelo Branco is a trachytic dome formed roughly ten thousand years ago, the result of a coastal volcanic eruption. The lava, too viscous to flow freely, piled up over the vent, creating this dome-shaped structure, connected to the island by a narrow isthmus.

Why “Castelo Branco” (White Castle)?

The name comes both from the hill’s castle-like shape and from the whitish colour of its heavily weathered trachytic rock, covered in pumice pyroclasts from the Caldeira volcano — a striking contrast against the island’s otherwise dark landscape.

A protected seabird nature reserve

The dome’s vertical cliffs, shaped by marine erosion, are nesting habitat for protected species such as Cory’s shearwater, Barolo shearwater, and common tern, and also serve as a spotting point for common dolphins, bottlenose dolphins, and loggerhead sea turtles. A restoration plan launched in the 1990s, and reinforced in 2013, has already removed accumulated waste and debris and controlled invasive plant species.

Natural pools next to the airport runway

At the foot of the hill, Castelo Branco Natural Pools offer tide-filled pools, an open-sea bathing area over a basalt slab, and two artificial pools fed by seawater. A rare quirk: since they sit right below Horta Airport’s runway, swimmers can watch planes take off and land up close.

Planning your visit

• Trail: Rumo ao Morro de Castelo Branco (PRC05FAI), a roughly 4 km loop starting and ending at Lombega.
• Pools: Caminho do Porto, Castelo Branco parish, with lifeguard supervision in season.
• Gear: hiking shoes, waterproof clothing, and sun protection for the trail.

Best time to visit

March to October is seabird nesting season, increasing your chances of a sighting.

Nearby highlights

Horta Airport and Queijaria O Morro cheese shop are a short distance away.

After Morro de Castelo Branco, continue north to explore more of Faial’s coastal natural pools, including Porto do Salão.

Learn more about diving in the Azores.