You can use where in asking questions.

–Where are you going?

Where can also be used in a dependent clause:

–I see the house where they live.

In the latter example, where is used to refer to a place, such as a city, state, country, room, etc.

NOTE: In dependent clauses, where can be replaced with in which, which ... in, that ... in, or nothing at all:

–The building where they work is new.
–The building in which they work is new.
–The building, which they work in, is new.
–The building that they work in is new.
–The building they work in is new.

Examples of Using Where

• I want to see the house where Thomas Jefferson lived.
• He's from the town where I was born.