Cu Mong Pass

Cù Mông Pass sits exactly on the old boundary between two lands. National Highway 1 runs from the former Bình Định down to the former Phú Yên, and the pass lies between them.

It is one of the shorter passes on the road through central Vietnam, but one of the richest in things to tell. It is only about 7 kilometers long, and its summit stands about 245 meters high. Even so, a traveler always feels it clearly: the sense of crossing a threshold and leaving one region for another.

The terrain explains why. On one side the mountain drops steeply to the road. On the other the land opens out gradually toward a lagoon and the sea. The pass has many slopes and sharp bends. Before the tunnel was built, this was the most worrying stretch of National Highway 1 on that part of the north-south route.

The Cù Mông Tunnel is the newest part of the pass. Construction began in September 2015. The whole route is more than 6.6 kilometers long: 2.6 kilometers run inside the mountain, and the approach roads add just over 4. The design speed is 80 kilometers an hour. The tunnel took away an accident black spot on the pass and cut travel time considerably.

A car that takes the tunnel spends only a few minutes under the mountain. A car that takes the old road over the pass learns why people call Cù Mông a "heavy" pass. The slopes are steep, the bends are sharp, and with a heavy truck ahead, a driver needs patience.

In administrative terms, the pass was long the familiar boundary between Bình Định and Phú Yên. From 2025, after the administrative reorganization, Bình Định joined Gia Lai to form Gia Lai Province. Phú Yên joined Đắk Lắk to form Đắk Lắk Province. The old names live on in history and local memory, as the two lands that the pass once marked apart.

A legend ties the name Cù Mông to the shape of the mountains, and each place tells it a little differently. Some tales speak of a dragon, some of mountains shaped like an animal, some of stories from long ago. These are popular explanations, colorful and rooted in the place, and they are best heard as legend, not as verified history.

What the pass really shows is how a road can change daily life. Before the tunnel, traffic here was slow, heavy and risky. Since the tunnel opened, traffic flows more freely and travel time has fallen sharply. The pass has slowly become a place to stop and look at the land, for those who want to see the terrain instead of only driving fast.

A stop that faces Cù Mông Lagoon shows the geography of the South Central Coast at a glance. Mountain meets sea, the lagoon opens between two lands, and National Highway 1 stretches below, linking the whole journey.

Cù Mông is not as grand as the Hải Vân Pass. Nor is it as long as the Cả Pass. But standing here in the wind and sun, a person looks down at the green lagoon and the road curving along the mountainside. Each pass on National Highway 1 is a chapter of its own in the country, and this is one of them.