Margaret “Peg” Armstrong, principal of Wiscasset Middle High School since October 2015, resigned July 26 in a letter to Superintendent Terry Wood, Wiscasset School Department Administrative Assistant Stacey Souza said Thursday.

WMHS secretary Beth Smith said Armstrong will work for School Administrative District 75, which serves Harpswell, Topsham, Bowdoin and Bowdoinham, as its interim assistant superintendent.

Smith said the process had been in the works much of the summer, but the letter did not go to Wood until SAD 75’s board confirmed the appointment last week.

Armstrong has already left the Wiscasset School Department, Smith said.

Reached at her new office, Armstrong said she learned of the job June 28. She said she hadn't been looking to leave Wiscasset, but when she saw the job description, it seemed like a good fit.

"I'll be sharing in district-wide professional development," a passion of hers, she said. "There are aspects of the position in which I'll be working with students with developmental issues and mental health issues, and my background is in clinical social work."

She said she was excited, but was sad to leave Wiscasset. "I've always felt very supported by the school and the community. I feel really good about the work we did at WMHS." She said she hopes the new administration will "trust the staff" to continue with the work they began in professional development over the last few years.

Corrected: Souza said the department has begun seeking applications for principal. The search will remain open until a suitable candidate is found, Souza said.

For now, Wood will handle the principal’s duties at WMHS.

Editor's note: This article originally stated Souza said the department had not begun seeking applications.