When colleges look at student's admissions packages, one of the things they factor into their decision is where you are from. Public and private colleges will differ in the amount of weight they give your home state, and whether or not they let it be a determinant depends on a number of different factors. Even though you can't do anything about this part of your admissions package, it is good to keep this in mind when first applying to a public or private university.
Why does it matter what state you're from?
For public and private colleges, they may have a certain quota they have to reach for out-of-state applicants. Private colleges generally have higher quotas than public colleges for out-of-state applicants. Both types of colleges value geographic diversity in their students because it might have an affect on what type of applicants they get in the future.
Out-of-state tuition is generally much higher, sometimes even twice the cost, than in-state tuition, colleges often have a hard time getting just 5% of students from different states than their own. Especially if the school isn't highly ranked or well-known for their sports or academic programs, getting out-of-state applicants can be close to impossible. Plus, for the college, if they are able to get more out-of-state applicants it means more in tuition getting paid to their college, which can be very important in times an economic downturn.
What does this mean for you?
What this means is that you may have a better chance of getting into a ranked school if you are an out-of-state applicant, over an in-state applicant with the same qualifications, experience, and personal background. Private schools generally prioritize out-of-state applicants more than public schools do, too.
Remember, though, that this isn't always the case and it isn't always one-to-one, meaning just because you're an out-of-state applicant doesn't guarantee you a position at any college. College admissions factors in a number of different variables when making their decision, so don't rely on your location to get you into college.
If anything, this is something that you should ask the admissions office of the college you are applying to. Most will probably tell you that it does, but this factor is so little that it won't tend to matter as much as the student might think. Above all, schools will look at your grades, extracurricular activities, intended major, and classes you have taken to determine the value you bring them as an institution.
One thing to keep in mind as well is that schools will sometimes offer students financial incentives for attending, but not just because of your residency classification. If you are a good out-of-state applicant, the school may offer you in-state tuition to attend, and sometimes even scholarships and help with tuition above that. This information will be included in your acceptance letter. Above all, don't be discouraged from applying to an out-of-state college, public or private, just because you don't qualify for in-state tuition.
If you do get an acceptance letter with some sort of financial aid package, make sure that you factor this into your decision when ultimately choosing the school you are going to attend. Also, don't just look at the financial aid package and say no, call the school and tell them about your situation. If you would attend if tuition were X amount of dollars less, let them know. They may be able to get you a better financial aid package, especially if you've been accepted into other competitor schools.
There is nothing wrong with asking, and there is certainly room for schools to work with you if you are a student whom they really want to attend their college. Even if they aren't able to get you anything better, you can still decide to attend that school. It doesn't hurt to ask.