Where 作為疑問詞，用來提問；there不能作為疑問詞,用作副詞，表示“在那裡”。

Where are you going?

Where did you get it?

I got it there.

where作為關係副詞，用來連線主從句；而there可以指副詞，表示“在那裡”，有指向前文所提及的地方的關聯意義。

They had a wonderful time on the beach, where the air was fresh, the water blue and the people happy.

They had a wonderful time on the beach. There the air was fresh, the water blue and the people happy. (There 位置，還可以在主語後，或句子末尾）

Where 可以引導狀語/賓語/主語從句； there可以用於自己的特殊句型there be...(表示存在）

I cannot remember where I put my keys.

Where you got it is not important any more.

Please put it back where you found it.

There are some interesting books.