What is the difference between direct and circumstantial evidence?

Direct evidence is evidence which a person actually observes. Circumstantial evidence is evidence that was not observed but from which a judge or jury could infer that an incident occurred. The most common example in a criminal trial of circumstantial evidence is footprints in the snow. While a person may not have seen another walk across a field during a snowstorm, the fact that there are footprints in the snow is circumstantial evidence that a person did so.