American travelers visiting Canada can get a shock at the border if they have a criminal record (even if it was a misdemeanor like a DUI), they can be denied entry to Canada.
At Pardons Canada we receive numerous calls and emails each month from Americans who were denied entry to Canada due to their criminal record. This is particularly concerning for those with loved ones in Canada who they can no longer visit or business people who cannot travel to Canada to conduct business.
The good news is that there is a solution. We need to apply for a deemed rehabilitation waiver to allow the person to re-enter Canada. The process takes time and it is complicated but we are skilled at preparing the application so that the Canadian government will approve it.
Here is a timely news article about how people from the US are denied entry to Canada if they have a criminal record:
http://www.startribune.com/you-can-be-kept-out-of-canada-for-this/397835451/