John Wendel Warner, who is 44, of Eagle Mountain, Utah, pleaded guilty for failing to report he had a firearm when he was stopped in January at the border crossing in Coutts, Alta.
After his vehicle was searched and a handgun was found, Warner said he "forgot" to declare the weapon.
He was fined $4,000 and prohibited from owning or possessing any firearms in Canada for 10 years.
A woman moving from Colorado to Alaska pleaded guilty to making a false statement to a Canadian border official in October 2013.
Lana Gail Bradley, 45, was fined $3,000 and is prohibited from owning or possessing any firearms in Canada for a period of five years.
She was driving a motor home and was pulling a trailer that contained all of her belongings when she was stopped at the Coutts border.
Bradley was asked twice if she had any firearms and said no both times, but then admitted later she had a hand gun. Customs Officers found the gun in a suitcase during a search of her trailer.