For purposes of the Constitution of Maine, Article IX, Section 8, Subsection 3, a regional school unit is a school administrative district.
Me. Rev. Stat. tit. 20-A, § 1453
Status of regional school unit
PL 2007, c. 240, Pt
Official source: Maine Legislature. Reproduced from public-domain Maine statutes; confirm against the official source for the current text. Not legal advice.