Everyone has an accent! I have heard people in Illinois, Iowa, Wisconsin, Indiana, Missouri, Kansas, Nebraska, Ohio etc. all say they do not have an accent......but of course they do - they just think everyone else sounds funny!
I had a professor in college who taught linguistics who would have you read a certain paragraph and could pinpoint not only the state, but what part of it you were from. If you tried to fool him he knew. I have heard at least a hundred different accents in my state alone. By the way, this test and several others I have taken says I speak with a middle Canadian accent. I am from Southern Illinois.