How are street address numbers assigned?

Walking to the train this morning, I noticed that 4 consecutive houses bore the numbers 377, 379, 389, 397. It got me wondering how specific house numbers were assigned. And if a homeowner wished, could they change theirs?

For example, could the owner of the 3d house listed above change his number to any odd number between 381 and 395? Does he have to request permission to make such a change? Who would he ask - the local government? The Post Office? And if he just changed the number and started using that as his address, would the PO keep delivering his mail? It seems that for most legal purposes, the legal description is far more important than the address.

I’ve heard in the past of instances where numbers were changed. For example, in Chicago I believe the old Palmolive/Playboy building was 666 N. Michigan. When Playboy moved out and the building was rehabbed, I recall them changing the address to something less beastly.

And I recall hearing that all of these new places that have vanity addresses such as 1 xyzcorp. Place have to have a “legitimate” street number for emergency response purposes.

This is going to be one of those questions where the answer is, “It’s up to your local jurisdiction.” AFAIK there is no set method of assigning house numbers, and local agencies have considerable latitude.

In my home town (a fairly rural area), the numbers were assigned by the fire department as the distance from the main road. Pretty logical, actually: if the fire was at 10000 West Street, they only have to measure the distance, and any vacant lots wouldn’t mess things up.

On my street, there is a 2021 1/2 because some houses were numbered from one end, and others from the other. The two systems led to two 2021s.

But as long as the post office and emergency services are notified, you could probably use any address you want. Also, when a street is being built on, there is often a zoning plan that designates the lots, even if not all of them have buildings on them yet.

In the US it’s very common for numbers to go up by 100 for every block from some central street. In the UK and in Australia, it’s more common for numbers to start at 1 no matter how far they are from the centre of town, and go up by 2 for each house on each side of the street – I’ve twice lived in houses numbered 1 in Australia. Within the US system, especially with a site the occupies a large part of a block, there’s room for choice, so you might choose 666 when a more logical choice would be 650. Within the UK and Australian systems, if a site occupies several consecutive sites it might give itself the range, e.g., 102-106, as the address.

If you need to interpolate, I’ve only seen 1/2 used in the US, while in the UK letters are more common, e.g., Sherlock Holmes’ address 221B Baker Street, which was presumably between 221A and 223 Baker Street.

In Colorado, it’s the County Government.

In fact, it’s me (or someone in my department)

We use a mile post system. Addresses are based on distance up the road. In towns however, we try to use the block system.

It’s kind of a mess in some areas, in the past, different jurisdictions would do there own thing.

When we have to, we will change an existing address. Pisses people off quite a bit.

Fairfax County, Virginia changed back in the 1960’s and made every street reflect a grid based on the distance from the northern and eastern edges of the county. So now I live in the ten thousand block of my one block street, and I have a friend who lives in the 13,000 block of a cul-de-sac.


“In my opinion, there’s nothing in this world, Beats a '52 Vincent, and a red headed girl.” ~ Richard Thompson ~

Back in the mid-70’s, my hometown standardized all addresses based on cross-streets and a few other data points. You got a notice in the mail that as of such and such date, your address was changed to whatever. This was to aid firefighters and police in figuring out where you were. It was a great improvement. Now, all new developments are given very specific addresses.

I live in Warren County, Missouri. Addresses are assigned by the 911 Dispatch Center. They notify the Post Office. I live on a private road that connects to a County Highway. Numbers seem to increase from North to South on this highway. I’ll have to check some of the other highways for consistancy.

Former city employee.

All the property in the municipality is listed, parcel by parcel, in “plat books.” Each page of the books covers a section of the city. Virtually every parcel has frontage that touches a street or right of way.

The frontages are assigned street addresses as a matter of course. However, the owner can legally use any (odd or even) address in the block of numbers assigned to the parcel.

So the answer to Dinsdale’s question, “For example, could the owner of the 3d house listed above change his number to any odd number between 381 and 395?” is “yes.” I assume that the owner would have to file some official change of address form with the municipality and post office to ensure that all the addresses matched up, but it’s no big deal.

Plat books are amazing things. In my city they dated back to the 19th century, were a couple of feet wide, and had all sorts of details about buildings, easements, rights-of-way, ownership, and more. You could spend hours pouring over them. They were also available to be viewed by the public.

This tends to be true only in cities that were created after the colonial period. When the government bought the Northwest Territory (which is Ohio and neighboring states) they surveyed the entire region to be able to more efficiently sell the land. Many of the towns and cities that were established formed along the grid lines and had First, Second, Third etc. streets. These often used an address system that corresponded to blocks for ease of finding one’s way around.

However, except for Philadelphia, laid out by William Penn on a grid system, most of the older cities grew organically and haphazardly. Even Manhattan doesn’t follow this pattern on its numbered streets, although you can find this in the outer boroughs.

Moving from Denver, CO to the Bay Area really screwed me up for a while. One thing I will grant Denver is a wonderfully uniform street name and numbering system extending all the way out into outlying suburbs. House numbers bumped up by 100 with each block and N/S numbers corresponding to numbered avenues. You didn’t even have to know the municipality a street address was in. I got used to that. By contrast, the Bay Area is a dreadful hodge podge where each municipality does its own thing, and numbers change from 5 digits to 3 digits to 4 digits without warning, or ascend for a while then descend again based on the whims of the municipality you are passing through, each of which centers its numbering on a different street.

Just to clarify a bit, Chicago, and most of the surrounding area, is on a strict grid. State and Madison downtown is 0/0. Every block in any direction increases by 100, with 8 blocks to the mile.

Most of the suburbs are also addressed in grids, although they do not all continue their numbers from where Chicago’s end. This generally becomes increasingly true the further you get from Chicago. Instead, most suburbs have their own 0/0 point from which their addresses radiate.

In my town, each 100 covers a pretty long stretch. Probably at least 2 “blocks”, although the length of blocks is not standardized as in Chicago.

Also, there is an overarching numbering system applied in unincorporated areas and in some subdivisions, where the addresses will be something like 23W2200 Main Street.

But back to the block in my OP. These 4 homes are all at least 50 years old. The block is fully developed, meaning that each lot is approximately 75-100’ wide, and in our village 75’ is the minimum width for a buildable lot. So none of these lots could be subdivided (at least without seeking a variance). Clearly “in-town” rather than rural.

It is hard for me to envision any kind of a rational system or decision-maker whereby 2 adjacent homes are numbered successively, and then the addresses of the next two differ by 10.

Shoulda previewed. Thanks for the informative post, Exapno. I read a book a while back - I think it was titled something like The Measuring of America. Was about the survey you describe, not only how it was conducted, but how it influenced land ownership and development, and vestiges of it that affect us today. Fascinating stuff. For instance, as I recall, the development of a reliable standard chain used in measuring was considered a huge advancement.

In the UK when you enter a road/street/whatever at it’s start the odd numbers are 99% of the time on the left beginning at #1.

Even numbers are across and usually start at #2.

If there is a substantial gap between, for example, 13 and the next house then what happens is that the local authorities determine how many DWELLING houses could fit into that gap.

So if they decide that 5 houses could fit in the next numbered house after 13 would be 25.

Should homes be built on the space at a later date they would be numbered 15-23.

On the other hand if 6 instead of 5 homes are built one of these would be numbered 15a, the rest as normal

Measuring America: How an Untamed Wilderness Shaped the United States and Fulfilled the Promise of Democracy, by Andro Linklater. Absolutely fascinating book. (For those who like that sort of thing. A bit dry otherwise.) Recommended.

I was unfortunatly raised in Denver, as it has spoilt me for finding addresses. (and for having a sense of direction that does not rely on the mountains) One place better, though, is Salt Lake City, Utah and it’s Wasatch Valley 'burbs… All addresses are given as two cartesian coordinates. East of West of State Street, and North or South of Temple (Ave?). There is no need at all to to give directions. As I recall each nominal block = 100 “address units” = 1/10 mile, so you can even use your odometer if there are no buildings or addresses posted.

Buffalo, New York actually uses a variation of the European address numbering system. Addresses are based on a street’s point of origin, not a central street or baseline. Addresses go up by 2 for every 15 feet the lot is from the street point of origin. If a street is extended in the opposite direction of the point of origin, the street extension will be given a different street name than the original section.

Confusing as hell.

My street and many streets around here have the odd numbers on one side, even on the other. Where my cousins live down the country (in Northern Ireland) they seem to have been assigned a randomly spaced number. So for example one house would be 112 the next one, one field over might be 117 or 120 or 125. My cuz was saying there’s no way 10 houses will ever be built between hers and her neighbour but the numbering allows for it anyway.

Montreal has a wiki that covers it’s street numbering:

St-Laurent Street, also known as the Main, is the zero-point for all east west roads, and the St-Lawrence River/Lachine Canal is the zero for north-south (as mentioned in the wiki, that leads to an interesting result for the streets that cross the canal…!)

It’s nice, to have some sense of where a building is simply based on knowing if a street runs east/west, and one address on it! Looking for 5678 De Lorimier and you’re at 3890? Walk north!

In each of the five boroughs of NYC, the power of assigning addresses resides with the respective Borough Presidents. They each have a topographical unit that handles these matters.

Residents and businesses can request certain address numbers, and as long as they fit within the range of numbers between the adjoining addresses, they’ll usually – but not always – get them. I’m pretty sure the BP has the *legal * power to assign numbers however he/she chooses, sequentially or not. But most of the time (meaning 99.99999% of the time), he/she will just follow the normal consecutive-numbering convention so as not to come off as a dick and piss off the USPS, the emergency services guys, and the residents in the neighborhood.

Now, sometimes a BP will assign a vanity addresses to make a developer or other constituency happy, but that usually involves creating a grand-sounding address out of whole cloth, not violating the normal numbering sequence of regular street.

If you want to see the sometimes wacky results of NYC’s Borough-centric addressing system, travel the borderline between Brooklyn and Queens. The border-defining streets will have one sequence of numbers on the Brooklyn side, and an utterly, utterly unrelated sequence on the Queens side!

I believe that the B indicated an upstairs flat, not an address between 221A and 223 Baker St.

We lived on a short enough street in a small Ohio town that we didn’t use a number at all when I was growing up. But then my in-laws, who live in a small Vermont town, had to change their street number (from 7 to 29, in their case) a few years ago when the 911 system was set up countywide. Many other homeowners and businesses had to do the same, amid much grumbling.

When Ronald and Nancy Reagan moved to LA after he left the White House, their house was at 666 Whatever St. They asked the city to change it to 668, which was speedily done. No Antichrist there!

The Apple Computer corporate HQ address is 1 Infinite Loop, which I think is cool.