PROVIDENCE, R.I. (WPRI) – Don’t blink driving past ZIP code 02902 in Providence. You might miss it.

The ZIP code encompasses The Providence Journal building at 75 Fountain St. and nothing else, representing one of three unique designations in the city. The other two, 02912 and 02918, represent Brown University and Providence College, respectively.

The tiny geographic postal areas are known as “unique ZIP codes,” and the U.S. Postal Service occasionally assigns them to businesses and institutions with high volumes of mail. Datasheer, a New Jersey company that operates Zip-Codes.com, says there are 2,095 unique ZIP codes nationwide.

“They are rare, but not without precedence,” USPS spokesperson Maureen Marion wrote in an email.  

Beginning after World War II and into the earliest days of suburban sprawl, the postal system’s two-digit “zones” became insufficient as the volume of mail grew across the country, Marion explained.

Enter the more specific five-digit ZIP code, introduced nationally in 1963. It wasn’t mandatory but became prevalent thanks in part to a popular public campaign pushed by what was then known as the U.S. Post Office Department.

Around that time, the postal system decided to also introduce unique ZIP codes for specific destinations, Marion said. The unique areas – including the three in Providence – are scattered across the country.  

The White House has a unique ZIP code (25000), as does LaGuardia Airport in New York City (11371) and the IRS in Holtsville, New York (00501). The JW Westcott II, a 45-foot contract boat that delivers mail to passing ships on the Detroit River, has its own unique ZIP code in Michigan (48222) — the only floating ZIP code in the United States.

The generic 12345 ZIP code often included on children’s letters to Santa Claus in the North Pole is technically assigned to General Electric in Schenectady, New York.  

“Over the years, many, many Santa letters have been sorted to that ZIP code and secret Santa responses have been provided by the elves among the GE retirees,” Marion quipped.

Retired longtime Providence Journal columnist M. Charles Bakst said the unique ZIP code at 75 Fountain St. was something he thought about at times while working there beginning in the 1960s.

One of his earliest assignments was to cover a visit from Postmaster General W. Marvin Watson, who also served as President Lyndon Johnson’s unofficial chief of staff. The assignment made him think about the 02902.  

“I remember it always felt like we were working on an island, or within our own city walls,” Bakst said.

“We were surrounded by the ’03,” he added, referring to the 02903 ZIP code assigned to most other parts of downtown Providence.

The Journal, which has declined in print circulation over the years, no longer occupies the entire iconic Fountain Street building, so it now shares 02902 with other outfits, including Infosys and Virgin Pulse.

And while less mail is likely making its way through the Journal building compared to three decades ago, thanks to the pervasiveness of email and other forms of e-communication, that doesn’t mean the 02902 — or any other unique ZIP code in the United States — is likely to disappear any time soon.

“The expectation is that it will be a long-term, mutually beneficial arrangement. That is why we don’t go that route often,” Marion said. “We expect the decision and the need to last.”

Eli Sherman (esherman@wpri.com) is a Target 12 investigative reporter for WPRI 12. Follow him on Twitter