How do you say "which is" in Japanese?
When speaking/writing in Japanese, I feel like I'm limited as far as sentence structure and being able to express an idea in more than one way.

How do you say "which is", as in, "I am attending x high school, which is 10 miles away from my home."

Question

How do you say "which is" in Japanese?
When speaking/writing in Japanese, I feel like I'm limited as far as sentence structure and being able to express an idea in more than one way.

How do you say "which is", as in, "I am attending x high school, which is 10 miles away from my home."

Answer

"I am attending x high school, which is 10 miles away from my home."

I would say x高校へ行く予定。（そこは）家から10マイルなんだ。or 家から10マイルのところにあるx高校へ行くつもり。

Answer

そこは/be used for place、それは/be used for something
In your case, そこは is correct. I'll give you another example.
"I bought a book which is written in Japanese." This case, それは is correct.