Why are so many Michigan house numbers 5 digits?

That “98 1/2 Street” thread made me think of this. I have a business where I ship things nationwide, and had noticed that even before I started doing that. You usually don’t see 5-digit house numbers unless it’s a house on a street number higher than 100, from what I’ve seen, except for Michigan. There, it’s almost always a 5-digit number.

Any particular reason why? Just curious.

I can’t speak to Michigan but I always thought 5 digit addresses were fairly common even in areas without numbered grids. There are none locally in Monroe County, and that’s what I thought was unusual.

I assume it has to do with grid streets. In Bellevue WA where we lived back in the 70’s we had a 5 digit address (17207) because we the 7th house on our street at the cross with 172nd street. I assume it’s the same near major cities in Michigan.

The OP is wrong. Around here 5 digit house numbers are everywhere that was developed outside incorporated cities. The town I live in was developed a hundred years ago, but only became an incorporated city 20 years ago. Every address is 5 digits.

I’m in Warren County Missouri. They used to have addresses starting with 2 digits and going up as required for the length of the road.

Now all addresses are 5 digits or more. Something to do with emergency vehicle dispatch.

I grew up in a part of the San Fernando Valley. In my particular neighborhood, my street and all the other streets parallel to that had 5-digit numbers. All the streets perpendicular to that had 4-digit numbers. I never saw (or at least never noticed) any house numbers of 1, 2, or 3 digits until I went off to college in another city. And then I thought that was weird at first.

Five digits just means that you’re about five miles from City Hall or the county seat. Much of Fairfax County, VA has five digit addresses.

I suppose everywhere has its own way of doing things that makes sense locally. In the UK, it’s rare to see street numbers with more than three digits because, even a continuous road, will often change its name after a mile or two. (Bristol Rd will become London Rd etc.) Often this is because road changes joined up what were separate roads to make one, or the road crosses a boundary into another district.

Our Postcodes are similar to Zip codes but define a much smaller area. A 6 or 7 digit Postcode together with a street number will nearly always identify a house. Many businesses have their own unique (sometimes more than one) postcode. The BBC for example is “London, W1A 1AA” If you put nothing else but the postcode on an envelope, it would get there.

There’s also some math reasons attached.
Typically “blocks” are 100 building numbers apiece. And there’s about 8 or 10 blocks to a mile. So a mile is ballpark 1000 building numbers.

Given a grid going for several miles with continuous numbering, there will only be one block with two-digit numbers, then roughly 10 blocks with 3-digit numbers. Then 100 blocks with 4 digit numbers. everything above that will be 5 or even 6 digit numbers.

That’s just how counting numbers work; for each additional digit there are 10x as many numbers.

In terms of miles it’s like this: there will only be 1/10th of a mile with two-digit numbers, then roughly 1 mile with 3-digit numbers. Then 10 miles with 4 digit numbers. Everything from 10 to 99 miles will be 5 digits, while everything at/above 100 miles will be 6 digit numbers.

All this is true regardless of whether the streets are named with numbers (12th St, 125th Ave, etc.) or with settler’s names, or letters, or whatever.
Large grids that don’t get renumbered across an entire county (or sometimes even bigger areas) are common in the rural flat parts of the US. They’re less so in mountainous terrain or areas settled densely in the 1800s, such as the east coast.

Finally, this effect runs both north/south and east/west. So in a grid that’s 10x10 miles = 100 square miles, you’ll have 1/10x1/10 = 1/100th of a square mile of 2-digit addresses. Then 0.9x0.9 = 0.81 square miles of 3-digit addresses. And finally 9x9 = 81 square miles of 4-digit addresses. Assuming all lots are occupied and are the same size (big assumption here) this means 4-digit addresses outnumber 3-digits by 100x. And 3-digits outnumber 2-digits also by 100x.

If the grid is bigger yet, say 40 miles by 40 miles = 1600 square miles, then 1500 of those 1600 miles are purely 5 digit addresses. 40x40 is very roughly a typical county size in much of the Midwest.
Bottom line:
The OP should be wondering why he/she ever sees *non-*5-digit addresses in the rural parts of the US.

I can’t speak for Michigan, but in Edmonton (and I think in Calgary) there are lots of 5 digit house numbers because (most) addresses are based on the street (going North-South) and Avenue (East-West) that the address is nearest to. For instance, 11325 85 Ave. NW (address chosen entirely randomly) would be on 85 Ave NW near 113 St.

PS Wasn’t there a similar discussion about addresses not that long ago, or am I misremembering?

Very late edit:

I fuxxored up some of my math but the essential point remains: Given a large area without renumbering, there are vastly more potential addresses with big numbers than with small.

Are you thinking of this thread West 98 1/2 Street? - Factual Questions - Straight Dope Message Board from 2 days ago that the OP mentions but didn’t link to? :slight_smile:

This might be true in some grid systems but won’t work elsewhere.

The vast majority of the Northeast developed before the Jefferson grid started being applied in the Northwest Territories (Ohio and points and westward) and then elsewhere. Numbering is different here. Some places rename roads or start a new numbering system every time the jurisdiction changes. Route 1 in Connecticut often does both. You have to know what town 1610 Post Road is in because there may be a half dozen of them along the route.

On many longer continually numbered streets, numbering goes up very slowly because there was no custom of starting a number with a cross street and older custom was to bump up by two. The third block from downtown may have addresses like 52 because it was the twenty-sixth building. No Rochester street ever gets to five digits. Some do in Buffalo, but they are much more than five miles from City Hall when that starts.

Grid cities and non-grid cities are utterly different.

I seem to remember reading something that said the 5-digit addresses were chosen by and could be mapped to geographic coordinates, but I’ll be damned if I can find it now.

most of (at least) the Metro Detroit area follows the same format, though it can “reset” at certain points (county line, etc.) Though I don’t believe it’s mandatory, places like the Grosse Pointes and Royal Oak have 3- and 4- digit addresses.

I have a four digit address here in Arkansas. The numbers on the same street are 100s off. We were told it had something to do with 911. Before we had a 911, our addresses were all Rt # box #.

I think that’s the same in NorCal. And it would seem that most housing was developed outside incorporated cities because most homes have 5 digit numbers. San Jose certainly has a habit of gobbling up neighborhoods and incorporating them.

In neighboring Loudoun Country, an address with one, two or three digits means that you live within the limits of one of the seven incorporated towns and that you have to pay real estate and personal property taxes to the town as well as to the county. At least this is true for six of the seven towns. I’m not sure if Hillsboro collects taxes or not.

The ranch house where I was born was 1943. We were a mile south of the county line on a major high way. Our mail came out of Watsonville The homes along the highway about a mile south of us received their mail out of Salinas. I think the numbers started at the divide between the post offices and ended at the county line where the mail came out of the San Juan post office. In an emergency situation it made it hard for the sheriff’s deputies to find the ranch house.

At one time the numbering system was based on the postal route. The number started at the beginning of the route and increased by one number each house. At one time the ranch house was box number 97. When a house was added in the route there would be either 97A or 97 1/2. as more and more houses were added that would get too complex and they would renumber the route and each house would have a whole number. Problem was address had to keep changing. My Birth certificate states the address where I was born as box 131 route 4.

Some time after I was born they changed to the fixed numbering system. And that varies from area to area. Some areas the number increases by two every 10 feet, some by two every 25, or 50 feet. And in the same city different sub divisions use different increase multiplayers. You can go down one street in San Jose and most houses will be 2 numbers different then the one either side. And another street they increase by 4,6 or 8.

In New York City, the address systems can be different from borough to borough.

In Queens, the address system gives you a fair amount of information (as opposed to Manhattan, where “900 Third Avenue” doesn’t tell you where on Third Avenue the building is, and Third Avenue is a long, long street).

So, you might see an address in Queens like “34-22 92nd Street.” This tells you that the building in question is on 92nd Street, at 34th Avenue, and it’s building number is 22 (which doesn’t mean that it’s the 22nd building on the block – I have no idea what the formula is for building numbers).

Building numbers generally start at 01 on one side of the street and 02 on the other and go up by one for each lot, not building. So 34-22 92 St is built on lot number 22, which is the 11th lot starting from 34th avenue. It’s not always the 11th building though - if a building and its property takes up lots 20,22 and 24, it may have any of those numbers and the ones is doesn’t use are skipped.