whereabouts; what part; which area
Asks about a physical location or a general area within a larger context. Often used when the speaker expects an approximate answer.
Whereabouts is the station?
What part (of your body) hurts?
how much; what point; to what extent
Asks about a degree, amount, or stage in a process. Common in questions about progress, understanding, or quantity.
How much of the work is done?
To what point did you understand the explanation?
どのくらい asks broadly about amount, extent, or duration, while どの辺 can specifically ask about a stage or rough point in a process.
どの辺り is a slightly more formal or polite way of asking the same thing as どの辺, with the same range of location and progress senses.
Standard kanji spelling; the most common written form.
Rarely used kanji form; learners should recognize it but use どの辺 instead.
Compound of どの (which) and 辺 (area, vicinity). The reading へん for 辺 is a common suffix meaning 'area' or 'around'.