Any person living in the United States who possesses a criminal record and wishes to travel to Canada will need a Temporary Resident Permit. This is valid up to one or two years. One may also apply for a Rehabilitation. This document is a permanent approval, and allows hassle free border crossing into Canada.
The Canadian Government will look at each application individually. They will consider the following factors:
A Temporary Resident Permit may take up to 12 months for processing. It is important to note, if you've been denied entry in the past, you must have an approved permit to cross in the future as you may risk prosecution and/or deportation.