At many of the more selective schools (state flagship level and some private schools), students need to apply specifically to an engineering major or to the engineering division. Otherwise, if one enters the school outside of the engineering division, it may be difficult to switch to an engineering major (need a high GPA or competitive secondary admission process). It is best to check whether this is an issue at each school before applying and matriculating.
Engineering majors often have long prerequisite sequences, so even if entering the major is not an issue, the student needs to be careful to make sure that s/he is on track to graduate on schedule in the desired major.