If you were to find out which Ivy League university is the easiest to transfer you, would you consider that valuable information? Will you be transferring from community college or another university? Let me be the first one to tell you that transferring to any Ivy League university isn't easy, but there are some that are significantly more accessible than others. For a list of Ivy League schools that accept transfer students, see this post.
Before I tell you which universities are easier or harder to get into, understand that you should not let this effect your decision. The most important factor in your decision for transferring should be if the school is a good fit for you or not. Will that school help you fulfill your career goals? Will you thrive in the school's unique culture? Will you be comfortable in a small town or large city? Does this university have clubs that you're interested in? These are all factors that your decision should be based on, not just which university is easier to get into.
With the right steps, you can transfer to any university (regardless of the numbers). See this community college guide for proof.
The Hardest Universities to Transfer Into
As you might expect, transferring to Harvard University, Yale University, and Brown University are of the hardest to get into. This is mainly because, as they openly state, transfer admissions is more competitive than freshman admissions, posting transfer acceptance rates as low as 1%. They attribute this low acceptance rate to their high retention rates (meaning that students come back for their sophomore and junior years). Universities with lower retention rates have more spots to fill the next year. Don't be fooled though; a low retention rate does not have a direct relationship with how good the school is, but we'll get back to that later.
That being said, to find the easiest university to transfer into, you'll want to look at the university with the most spots available to transfer students. The more spots available, the better chances you have.
The Easiest University to Transfer Into: Cornell University
Having a lower retention rate, Cornell University accepts the most transfer students out of all the Ivy League schools. Cornell is the easiest to get into because they have more spots available. However, Cornell is not the easiest Ivy League school to do well in. Keep in mind that many students drop out because they are not able to keep up with the intense academic requirements. Aside from being very competitive, it's also located in up-state New York, distant from major cities.
So just because Cornell University is the easiest Ivy League school to transfer into, that doesn't mean you should only apply there. Research which schools are best for you. This way, you'll have more options that you'll be happy with. Then, once you're accepted into UPENN, Cornell and Dartmouth, you can decided which school to transfer into.
Check out this community college transfer guide to learn how to get into any Ivy League university you want.