
Brittany W. answered 04/13/19
Dedicated to you and your legal education.
An ABA-approved law school is a school that has met all requirements as set forth by the American Bar Association which essentially states that the education you are receiving at law school "X" is essentially the same, or of a high standard, as any other law ABA-accredited law school in the country when it comes to both legal knowledge and practice legal skills.
Almost every U.S. State requires that you attend an ABA-accredited law school before being able to sit for the bar. California is the most well-known exception. In California, someone may attend a non-ABA-accredited law school and still qualify to sit for the bar exam. Also in California, someone without even a law school or college degree can become eligible to sit for the bar if they complete an apprenticeship - a very long, and rigorous apprenticeship (if you Google Kim Kardashian West right now, this exception will come right up). Some states will allow you to attend a non-ABA-accredited law school and then petition that state's law examiners board to be able to sit for the bar; however, it is very rare that states permit this.
Reasons to attend a non-ABA-accredited law school vary. Some of the most common I have heard are: to allow the person the opportunity to see if law school is something they actually want to do; to give them additional time to study for the LSAT while giving them experience studying for law school courses; for someone wanting to sit for the bar and practice only in a state that permits non-ABA-accredited graduates to sit for the bar; or for people who want a law degree but don't want to become lawyers.