twin-tube tunnel under the Hudson River connecting Canal Street in Manhattan, New York City, with 12th and 14th streets in Jersey City, N.J. The tunnel was completed in 1927 and opened for traffic on November 13 of that year. It was named for Clifford M. Holland, the engineer who designed it. The north tube is 8,558 feet (2,608 m) long and the south tube 8,371 feet (2,551 m) long. The roadway is 20 feet (6.1 metres) wide and reaches a maximum depth below mean high water of 93 feet 5 inches (28.5 metres).

Considered a notable engineering achievement because it solved the problem of ventilating a long vehicular tunnel, it has 84 powerful fans capable of replacing air in the tunnel every 90 seconds. The polluted air is drawn off through a duct in the roof of the tube with the aid of suction fans. The system was severely tested on May 13, 1949, when a truck loaded with poisonous and flammable carbon disulfide caught fire in the tunnel and exploded. Despite the destruction of 23 trucks and the ruin of 500 feet of tunnel ceiling, no fatalities resulted.