Mountain pass · Van Ninh
Ca Pass
Đèo Cả
Ca Pass (Đèo Cả) is a pass on National Route 1 in south central Vietnam, crossing the Dai Lanh range of the Truong Son system where it falls to the sea. Vietnamese Wikipedia gives the pass a length of 12 km and a highest point of 333 m[1]. The southern side lies in Dai Lanh commune in Khanh Hoa province and the northern side in Hoa Xuan commune, which Vietnamese Wikipedia and OpenStreetMap both place in Dak Lak province[1][2].
Since 21 August 2017 most through traffic has used the Deo Ca road tunnel beneath the pass. The main tunnel is 4.1 km long and, with its approach roads, bridges and the 500 m Co Ma tunnel, the project runs to 13.5 km and cost 15,603 billion VND[3].
French colonial documents call the pass Col Babonneau, and it is also known in Vietnamese as Đèo Cục Kịch[4]. English Wikipedia describes it as the second most difficult pass in Vietnam after the Hai Van Pass and records that the Nguyen pushed their southern border down to the pass in 1611[4].
Geography
The pass carries National Route 1 over the Dai Lanh range at the point where the mountains drop into the sea north of Van Phong Bay. Vietnamese Wikipedia gives the length of the pass as 12 km and its highest point as 333 m[1]. No published figure was found for the area of the massif the road crosses or for the height of its highest summit.
Published coordinates for the pass differ. English Wikipedia places it at 12°52′16″N 109°23′57″E[4]; Wikidata gives 12.8792°N, 109.2778°E[6]; and OpenStreetMap traces the road over the pass through 12.8451°N, 109.3897°E[2].
The provincial boundary
The pass has long carried a provincial boundary. Vietnamese Wikipedia records that in 1997 the boundary between Phu Yen and Khanh Hoa provinces was drawn from the foot of Da Den, following the watershed line to the summit of Hon Nua, with Vung Ro on the Phu Yen side[1].
The sources disagree about which province lies to the north. English Wikipedia gives the pass's location as Phu Yen province[4], a form that predates the administrative reform of 1 July 2025. Vietnamese Wikipedia names the commune on the northern side as Hoa Xuan in Dak Lak province[1], and a reverse lookup of the road on OpenStreetMap returns the same province[2].
The Deo Ca tunnel
Work on a road tunnel under the pass began on 18 November 2013[3]. The Co Ma tunnel, 500 m long, was completed in September 2015; the main Deo Ca tunnel opened to technical traffic on 21 June 2016, and the whole scheme opened on 21 August 2017[3].
The main tunnel is 4.1 km long and the project including approach roads and bridges measures 13.5 km[3]. Each bore is 9.8 m wide and 6.5 m high, and the scheme carries four lanes[3]. Total investment was 15,603 billion VND, made up of 10,555 billion VND for the Deo Ca tunnel under a build operate transfer contract, 4,509 billion VND for the Co Ma tunnel, approach roads and bridges under a build transfer contract, and 539 billion VND for resettlement[3]. The operator is the Deo Ca Investment Joint Stock Company[3].
Speed limits inside the tunnel are 70 to 90 km/h for buses under 16 seats and lorries under 1.5 tonnes, and 60 to 80 km/h for other vehicles[3]. Tolls are collected at the Deo Ca tunnel toll station[3].
Landslides and closures
Heavy rain still closes the old road over the pass. Nhan Dan reported that National Route 1 over Ca Pass and the neighbouring Co Ma pass was blocked from about 01:30 on 20 November 2025 by landslides and deep flooding, with dozens of slip points on the two passes[5]. Traffic resumed at 14:00 on 21 November 2025[5].
The blocked stretch included Km1352+900, near the northern portal of the tunnel, and the Song Van bridge at Km1351+700, in Dai Lanh commune[5].
Questions and answers
Sources
Every figure in this article is cited to one of these pages, listed in order of first use, with the date it was read.
See also
- Dai LanhBeach
- Mui DoiCape
- Van Phong BayBay
- Expressways in Khanh HoaRoad
- Hon BaMountain
- Khanh Le PassMountain pass