California has most or all of the United States DL law schools. The requirement to practice law in California (and some other states) is that the law schools must be approved or accredited by the State Bar, not the ABA. However, the students are required to register with the state bar and make various appearances in California.
After practicing law for maybe 5 or 7 years, a lawyer might "grandfather" into another state.
There are various options for attaining a license to practice:
A few states allow apprenticeships instead of law school--after a few years of apprenticeship at a law firm, the applicant must pass the bar. I have also read somewhere that some states require either ABA accreditation or
the approval of the state supreme court.
There are also a few who study law through international DL law schools, then make up the difference at an ABA school, those of which usually require an additional 2 years for the JD. (Doesn't seem as if it would make sense to study law 6 years for a 3 year degree.)http://www.aals.org/