Alexandra Quick and the Deathly Regiment by Inverarity
Rated: 3rd-5th Years [Reviews - 201]
Summary: 
Alexandra Quick returns to Charmbridge Academy for eighth grade, angry and in denial. Unwilling to accept the events of the previous year, she is determined to fix what went wrong, no matter what the cost. When her obsession leads her to a fateful choice, it is not only her own life that hangs in the balance, for she will uncover the secret of the Deathly Regiment!
This is the third book in the Alexandra Quick series.
Alexandra Quick and the Lands Below by Inverarity
Rated: 3rd-5th Years [Reviews - 275]
Summary: 
Seventh grader Alexandra Quick returns to Charmbridge Academy. This year she faces bullies from another wizarding school, a secret Dark Arts club, and the machinations of her father, but her greatest trial yet awaits her in the dangerous Lands Below.
This is the second book in the Alexandra Quick series.
Alexandra Quick and the Thorn Circle by Inverarity
Rated: 1st-2nd Years [Reviews - 165]
Summary: 
Winner of the 2008 Quick Silver Quills Award for Best General Story.
The first book in the Alexandra Quick series.
The war against Voldemort never reached America, but all is not well there. When 11-year-old Alexandra Quick learns she is a witch, she is plunged into a world of prejudices, intrigue, and danger. Who wants Alexandra dead, and why?
This story is canon-compliant with the Harry Potter universe, but the characters and settings are all original. I've put a lot of work into envisioning a world as detailed as the original series; I hope you enjoy it.