Officers found a total of 75 firearms amid the man's belongings in the bed of his pickup truck, [Canadian Border Services Agency spokesman Sean] Best said.
Of the handguns - which are restricted or prohibited in Canada - four were loaded, said Best.
The CBSA also seized a blowgun, a crossbow and 12 high-capacity ammunition magazines.
Some of the long guns amid the man's belongings are legal in Canada, but it is an offence under the Customs Act to enter the country without declaring them.
CBSA officers arrested George Foster, 54, and turned him over to the RCMP.
Important warning about e-mails purporting to be from the adn.com staff.