How did Utah get its 801 area code? Why extra? And are there more to come? | Wbactive

801 is an identity.

Right now you can buy all kinds of 801 brand gear: t-shirts, hoodies, bumper stickers, phone cases, hats, you name it. Businesses from 801 Accounting to 801 Web Design have dialed the number to represent their businesses. Uinta Brewing’s 801 Pilsner is one of the best-selling beers in the state. All of this is because many, but not all, residents of the Wasatch Front have phone numbers that begin with 801, and somehow those three numbers lead back to their homes.

So I decided to study primaries as a phenomenon. How did Utah get the 801 area code in the first place? Why does Utah now have three area codes including 385 and 435? Couldn’t they just put all 3.3 million Utah residents in one code? And what does the future of the Utah primaries look like? Could we add another one soon?

The primaries story

In the 1940s, AT&T realized it had a problem. It was at the head of an empire of most phones in North America, but they had all outgrown these local and regional organizational groups, meaning each had their own numbering scheme. Human operators were a necessity for long-distance communications from both a technical and logistical point of view.

In particular, most US cities had an auto attendant center with a capacity of 10,000 numbers. In cities with more than 10,000 lines, customers dialed two letters — yes, letters — to indicate which operator they wanted to reach, and then the five numbers of their desired answering machine. For example, The Salt Lake Tribune’s phone number during this period was EM-31511.

AT&T wanted to make it possible to unify these regional numbering schemes. The obvious answer was to add more digits to customers’ existing numbers when people wanted to call outside their familiar local area. These were called primaries. AT&T also included 20 North American countries in the numbering plan later sensibly called the North American Numbering Plan, or NANP. (Mexico and some other smaller North American nations do not participate in NANP.)

Initially, only human operators were familiar with the area codes as a sort of back-end solution to the numbering problem. In 1951 came the first long-distance consumer dialing call, and the practice spread in the 1950s to the point where direct dialing was the norm by the early 1960s.

When they were first introduced, there were 86 area codes – necessitated by a combination of population and the number of numbering systems at the time. Of course, population growth over time forced the introduction of new area codes, and there are now 447 assigned area codes in the NANP.

Why 801?

So how did we come up with the good old 801 here in Utah?

When AT&T administrators thought about how the system should be built, they first looked at the technical side. In particular, how do you ensure that area codes are recognized as such and are not part of a normal area code? Well, no two-letter local telephone exchange contains a zero or 1. So they decided that any initial area code had to include those digits in the area code in the second number to ensure it wasn’t confused with an exchange. Second ones were assigned to states that were split, second zeros were assigned to states with only a single area code.

Then they looked at efficiency. They found that keeping the first and third numbers as low as possible for as many people as possible would be most efficient. People still used rotary phones to dial, and 8’s and 9’s took longer to dial than 2’s and 3’s. So it made sense to give higher density cities like New York area codes with lower digits like 212.

They also thought that grouping them geographically might help people remember the primaries. This was the proposed map when administrators first laid out numbers in early 1947:

Document from Bell Labs internal history “Bell Labs, Memorandum 40979” ( years/ page/n10/mode/1up)

Ultimately, however, this proposal was rejected. Why? Well, for two reasons. First, a system like this could increase miss-elections, since people bordering an area code might not easily remember the difference between 212 and 213, for example. More importantly, it wasn’t as flexible for new growth. What if California’s population exploded and the state needed dozens of area codes quickly? Area codes starting with a 5 would go out.

So in the end, officials distributed them with no real regard for geography. Utah received 801, a number with a large initial number but a small third number.

Original distribution of area codes. Notice how much effort has gone into making the digits in area codes take as little time to dial as possible. (

Why did Utah have to expand from 801?

That has always bothered me. Why do we even need more area codes than 801? With seven trailing digits, there should be room for 9,999,999 numbers in each area code, right? That’s far more than the 3.3 million people who live in Utah.

There are three big reasons for this.

• First, 9,999,999 numbers are not available. Zeros and ones are not allowed in the first digit of a seven-digit phone number. And the numbers 211 to 911 are reserved for services, and 555-0100 to 555-0199 are reserved for fictitious numbers. In the end, each area code has 7,919,900 numbers available.

• Second, there are more numbers than people. Businesses have phone numbers. Some people still have phone lines, fax machines, and even pagers with their own number.

• Third, we assign phone numbers quite inefficiently. In the past, local phone companies operated with blocks of 10,000 numbers at a time, all with the same three-digit prefix. They would assign an entire area code to a larger company and call it fine whether that company wanted 2,000 numbers or 8,000. This got messy and wasteful, so in 2002 the Federal Communications Commission said phone companies needed to distribute blocks of 1,000 numbers, using the same four-digit area code instead. This smaller block process helps, but still results in a decent amount of waste.

The most recent FCC report on the subject from 2019 data showed that 69% of 801 area codes were assigned. According to this report, traditional landline phone companies sit on a whopping 1,593,000 numbers in the 801 area code, while wireless carriers have 110,000 unassigned numbers. But even if you distributed them all, the amount of unassigned numbers in 801 still doesn’t meet the state’s needs — hence the 435 and 385 area codes.

Why 385 and 435?

In the 1990s, the introduction of fax machines, pagers, etc. forced NANP administrators to quickly outgrow the “zero or 1 in the second digit.” The first area codes outside of this rule were assigned in 1995.

By 1996 it was clear that Utah would soon need a second primary. There are two methods of area code extension: die Splits separates the geographic boundaries of a ZIP code into two, while the overlay puts a second area code within the same limits as the first. In 1997, however, the overlay method had not yet been used, so NANP administrators split Utah in two: Salt Lake, Davis, Morgan, Utah, and Weber counties would all remain at 801, and the rest of the state would become 435.

Why 435? Well, state civil service officials originally asked about the available area code 724 — in recognition of the July 24 holiday in Utah. But the 801-724-XXXX number block was already assigned to phones in Orem, and NANP administrators didn’t want to confuse the public in the 801 areas, which dial seven digits, nor the systems that would interpret those digits. Instead, the unassigned 435 was used.

“For us, primaries are buckets of numbers,” said a spokesman for the NANP administration when asked about 435’s selection. “It’s really boring, unromantic, hands-on work that needs to be done.”

The 385 area code became necessary in 2009, but by then the overlay had become commonplace, so that’s what NANP administrators did. It was also assigned in a boring, unromantic, practical way.

Number growth has slowed significantly thanks to the reduction in personal phones, fax machines, pagers, etc. The 801 and 385 area codes are currently expected to get us through at least 2032, while 435 is expected to get us through at least 2041.

Andy Larsen is a data columnist for The Salt Lake Tribune. You can reach him at

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