The U.S. attorney's office in Minnesota said 47-year-old Steve Shand had been arrested just south of the border on Wednesday while driving two undocumented Indian citizens.
U.S. border patrol agents soon came across five more Indians traveling on foot, one of whom was carrying a backpack belonging to a family of four who had become separated from the group as they all tried to cross the border.
They alerted Canadian police who found the victims - a man, a woman, a teenage boy and a baby - about 40 feet (12 meters) from the frontier with Minnesota. First indications are that they died from exposure to the cold.
"These victims faced not only the cold weather, but also endless fields, large snowdrifts and complete darkness," Royal Canadian Mounted Police Assistant Commissioner Jane MacLatchy told a televised news conference in Winnipeg, Manitoba.
Wind chill had driven down the temperature to minus 35 C (minus 31 F), she said.
The U.S. attorney's office said in a statement that the four victims had tentatively been identified as the missing Indian family.
The five Indian nationals explained they had walked across the border expecting to be picked up by someone and estimated they had been walking around for over 11 hours.
Shand has been charged with one count of human smuggling. He is next due in court on Jan 24.
(Reporting by Ismail Shakil in Bengaluru and David Ljunggren in Ottawa; Editing by Leslie Adler and David Gregorio)