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Post Offices in Union, IL
1 post office in Union, McHenry County · Data as of 09/23/2026
Post offices on this page
Post offices in Union at a glance
- With a population of 624, Union has 1 post office (16 per 10,000 people).
- It ranks 100th among 1,142 Illinois cities by number of post offices.
- Close by, Algonquin (2), Cary (1) and Crystal Lake (1) have post offices as well.
Post offices in Union
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Frequently asked questions
- How many post offices are in Union, IL?
- There is 1 post office in Union as of 09/23/2026.