It was back-to-school day for most central Maine schools on Wednesday, including George J. Mitchell School in Waterville, which welcomed more than 500 students in kindergarten through third grade.

Classes for most Waterville students, as well as others across the region, began Wednesday, as well as Winslow and Vassalboro, the two other districts in Alternative School Organization 92. Classes at St. John’s Regional Catholic School in Winslow and Mount Merici Academy in Waterville also began Wednesday. Temple Academy in Waterville begins next Tuesday.

Classes for lower grades began Wednesday in Oakland-based Regional School Unit 18, which also includes Belgrade, China, Sidney and Rome; Farmington-based Regional School Unit 9, which includes 10 towns; School Administrative District 49, which includes Fairfield, Clinton, Albion and Benton; School Administrative District 58, which includes Kingfield, Strong, Phillips and Avon; and other area districts began Wednesday. Grades 10 through 12 in those districts start school Thursday. Classes for all grades began Wednesday in Skowhegan-based School Administrative District 54, which also includes Canaan, Cornville, Norridgewock and Mercer.