Do I have to tell an employer on an application if I have a criminal record?

I have a criminal record in the United States, however I fall under the Holmes Youthful Trainee Act and my record is sealed. I was wondering since my record is in the United States and not in Canada, do I have to let employers know that I have a criminal record when asked on a job application? Will having this record in the Unites States affect me in any way other than being able to cross the border?