[willtel]

If you happen to drive across during peak times there is a good chance they will only check your docs and wave you through. If you try to cross when the border isn't busy and it is your first visit to Canada they will ask you to come inside and you have to speak to an agent about why you are going to Canada. That agent will have access to all of your American legal records but may not tell you that is the case. If they see any convictions they will question you about them and it is up to the agent to decide if you get in.

Most property crimes and usually DUI will prevent you from getting in. Once that happens you have to go back to the US then explain why you were denied entry.