Three men from Surrey, B.C., face drug charges after the discovery of a tunnel running from Langley to Washington state that authorities say was built to transport drugs between Canada and the United States.

Police say the 1½-metre high, one-metre wide tunnel runs from a metal Quonset hut just north of the border in Langley to an abandoned house in Lynden, Wash. – just 90 metres south of the border.

Francis Devandra Raj, 30; Timothy Woo, 34; and Jonathan Valenzuela, 27, face charges in the U.S. of conspiracy to distribute marijuana and conspiracy to import marijuana.

DEA photo of the tunnel running from Langley to Washington state.

They are accused of smuggling 42 kilograms of marijuana through the 110-metre tunnel across the border and into waiting vans.

Police say it's the first tunnel they've ever found along the Canadian border.

The tunnel runs from a depth of one to three metres and is reinforced with iron bars and 2 x 6 wooden planks.

Quonset hut in Langley, B.C

U.S. government agencies, including the FBI and drug enforcement officials, had been monitoring its construction for eight months, allowing its completion so that authorities could monitor the activities of those constructing it.

Investigators had even placed cameras and microphones inside the tunnel.

They moved in and sealed the tunnel on Wednesday, shortly after it opened.

It was constructed using shovels, as well as a winch and carting system to remove the dirt.