There's a time and a place for everything.
It’s Your Decision But Beware
Every time you write something, you as the author have to decide which words or phrases are appropriate. So it’s up to you to decide whether to use “which” or “where” in your particular sentence. If your audience expects formal grammar, use a “which” construction. If your audience is more relaxed, you can use “where.”
If you do choose to use “where,” though, you need to be aware of one common error. When you use “where,” you need to ensure that you’re talking about place, not time. For example, it would be incorrect to use a form of “where” in this sentence: “He was born somewhere around 1970.” The year 1970 is a time, not a place, so you would have to say, “sometime” instead of “somewhere.”
The Curious Case of the Misplaced Modifier & The Grammar Devotional
This podcast was written by Bonnie Trenga, author of The Curious Case of the Misplaced Modifier, who blogs at sentencesleuth.blogspot.com, and I'm Mignon Fogarty, the author of The Grammar Devotional—featuring 365 bite-size writing tips, fun quizzes and puzzles, and efficient memory tricks.
1. Stilman, A. Grammatically Correct. Cincinnati: Writer’s Digest Books, 1997, p. 244.
4. Garner, B. Garner's Modern American Usage. Oxford: Oxford University Press, 2003, p. 830.