Dear Suns Spots: Thanks so much for your helpful column.

I’m hoping you can tell me in what year the standardized two-capital-letter abbreviations for states began to be used by the Postal Service. They can’t tell me at the post office. Also, in what year did we start using ZIP codes? Thanking you in advance. – No Name, No Town.

Answer: The man who helped transform the American postal system in the 1960s and became a smiling symbol of efficiency turned 40 in 2003.

On July 1, 1963, what was then the U.S. Post Office Department introduced the Zoning Improvement Plan – much better known today as the ZIP code. The surging volume of mail in that pre-FedEx era, coupled with the increasingly diverse delivery system of planes, trains and trucks, forced the famously obstinate system to adopt the new code, the first significant change in the postal delivery system since the advent of airmail in 1918, according to the Scripps Howard News Service online at

And the man chosen to deliver the ZIP code sermon was none other than Mr. ZIP himself, a goggle-eyed, uniformed, cartoon letter carrier featured in television commercials and in the margins of postage-stamp sheets. As it turns out, Mr. ZIP became one of history’s great salesmen, achieving what is now a ZIP code compliance rate of more than 95 percent.

The U.S. Postal Service, which succeeded the Post Office Department in 1971, insisted that the changes were necessary. The private correspondence that had dominated the system since Benjamin Franklin took over as the first postmaster general in 1775 had been supplanted by a flood of business mail. By 1963, business mail constituted 80 percent of the total volume, consisting of utility bills, bank statements, credit-card bills and other pieces.

The post office simply couldn’t keep up. Sorting the mail, once performed at a leisurely pace on a train’s mail car, had to be done more quickly. So, in early 1963, the department adopted a coding system credited by most sources to Robert Moon, who began tinkering with the idea while serving as a postal inspector in Philadelphia and Chicago in the 1940s.

The final product was a fairly simple five-digit code. The first number designates a broad geographic area – the Northeast, for instance, is represented by a 0, while a 9 signifies the Far West. The next two numbers pinpoint population concentrations within those wide population areas, usually a state or several smaller states grouped together, while the final two designate specific post offices or postal zones in large cities.

Then-Postmaster General John Gronouski announced that the ZIP code would arrive on July 1, 1963. At first, attaching a ZIP code to a letter or package was optional. It only became a requirement for second- and third-class bulk mailers in 1967.

The Postal Service expanded on the ZIP code in the early 1980s with its ZIP-Plus-4 program. Originally aimed at bulk and large-volume business mailers, the new program added four numbers to the original five digits to achieve even better delivery.

Regarding your inquiry about state abbreviations:

The two-letter abbreviations came along as part of the ZIP code numbering program introduced in 1963, by the U.S. Post Office, as it was known then, to help speed mail delivery.

The idea was to limit the city and state line of an address to 27 characters for the sake of postal electronic scanning devices. The shortened abbreviations helped do this.

They were intended for use only on mail, but they’ve been used on billboards and on signs painted on trucks.

For example, “TN” replaced the long-standing “Tenn.” for Tennessee, but some use incorrect variations such as “Tn.,” “TN.,” “Tn” or even “T.N.”

Ironically, the specially created abbreviations aren’t required on mail anymore, except for mass mailers and special mail. Postal officials say, however, that the two-letter abbreviations are preferred. But the numbers, not the abbreviations, are the important part of the ZIP code.

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