All four main girls are played by actresses who are between the ages of 20 and 25. Maya is the most egregious example as the character is 16 but the actress, Bianca Lawson, is 31. Bianca Lawson also appeared on Dawson's Creek in 2000 playing a 16 year old at age 20 making her an original Dawson Casting actress.
Averted with Alison. Sasha Pieterse was 14 when she was cast. She's now seventeen, but since three years have passed in-story, she's still the same age as Alison.
Actually Inverted. She was 12 when she got the pilot.
Special mention goes to Troian Bellisario born in 1985 who is older than her teacher and her older brother Jason who were both born in 1986.
Directed by Cast Member: Chad Lowe (Byron, Aria's dad) directed "Touched By An 'A'-ngel," "Father Knows Best" (appropriately), "Kingdom of the Blind", "That Girl Is Poison," "Hot Water" and "Into The Deep."
Fake American: Samara and Caleb's dad are played by Australians Claire Holt and Bernard Curry, Jenna by South African-born/Australian-raised Tammin Sursok, and Emily by Canadian Shay Mitchell. This is not the case for Alison because while Sasha Pieterse was born in South Africa, she has spent most of her life in the United States.