Why does the IRS have its own zip codes in the United States?

Question

Why does the IRS have its own zip codes in the United States?

In: 76

Answer 1

They get as much mail as a whole neighborhood. And, the Post Office doesn’t have to deliver mail to each individual office at the IRS. Once bags of mail arrive at that zip code, the internal agency mailrooms take over. So, for efficiency, having that zip code belong ONLY to the IRS means the Post Office doesn’t have to separate out mail that’s NOT for the IRS but is in the same area.