A man named John Rea started a ranch in Orange, or was it Anaheim? He named it after his two daughters, Kate and Ella. I'm not sure of the history of Katella Avenue, but that's where the name came from.
Below is an e-mail we received back in the old days of OCThen.com, that relate to the name "Katella":
By: Brad, 15 Aug 2002If you have any to share about the Rea family and the name Katella, please click on "Post a Comment" below.
My grandma took care of Kate Ray. Kate had a sister named Ella. Katella's namesake. My grandmother told me when I was a little boy in the 60's that Katella grammer school was no longer there. But to answer your question about Ball Jr high. Yes it is still there.