The announcement, made by board of trustees chairman Dennis Baughman Wednesday afternoon, comes not long after the second-year charter school's opening day. Eshbach "put the whole thing together" Baughman said.
Eshbach was the first person hired by the board when the school was created, and was "able to build this school from nothing," Baughman said.
Eshbach will serve through Oct. 30. She said she decided to leave "on a positive not" in part to eventually pursue teaching at the college level.
"I'm very proud of where we brought the school," she said.
Baughman said her resignation came as a "surprise," but they are grateful for her service.
The departure should not knock the academy off its progress in applying for International Baccalaureate status, he added.
"This isn't going to deter us from going forward," Baughman said the board told parents in a letter.
The charter school, which draws from York City, Central York and York Suburban, serves grades K-3.