Addresses in unincorporated areas

[foodstamps]

Hey folks,

I've just started a GIS position at a state agency in Illinois, and my newbie status is about to come out by asking the following:

How do residents living outside of incorporated areas determine their 'City' address? I thought that it was based on the township that their residence is located in, but it looks like townships and other county subdivisions are only governmental boundaries, and not boundaries that are recognized by USPS. For example, a resident residing outside of a municipality but within the township of Prairie Du Long actually lives at xxxx Klein Rd., Smithton, IL, not xxxx Klein Rd., Prairie Du Long, IL.

So how does the USPS determine the 'City' of a rural address? Is it based on the zip code of the address? Is there a map (or better yet, a shapefile) that displays the 'City' boundaries in a particular state? I realize this may ultimately be a question that should posed to USPS, but I figured I'd start with this forum.

Thanks!

[Linda_D]

It's the post office that their mail goes through. I grew up in a rural area in the town of Persia, but our mailing address was always "Gowanda, NY" because that's where the post office was. People who lived a couple miles up the road got their mail from the Cattaraugus, NY post office, so that was their city mailing address. The post office for "Persia, NY" was gone prior to 1923 but did exist as late as the 1880s I believe.

[Blide]

The USPS doesn't supply any shapefiles as far as I know. There are some Zip Code and Census Designated Place shapefiles out there that could probably help you though. Then DOT websites tend to provide you with municipal boundary shapefile for a state. I think with those 3 things, you could probably get a good idea what "city" an address is located in. Those things may not match perfectly with what the post office has though.

I've also found some gray areas with cities. Like where I live, the post office has me in one city, the power company in another.

[Queen B]

It is a very individual thing per location. There is a shapefile of postal (Zip) boundaries. As far as "city" address' that seems to be a locality decision. Ours has been pushed to the fore front because of 911. Our county took the stand to have all 911 address' determined by the county. USPS assigns the Zip. It seems to work pretty well. All our postmaster know they are not allowed to create an address. This way works best for GIS also because you can do address ranges.

This can be a very contentious discussion so you may be walking into a hornets nest. Be careful going forward.

[foodstamps]

Thank you all for the information. I've found a Zip Code shapefile through NAVTEQ that contains a City field, and after comparing it with the input data, it seems to be (mostly) in agreement.

[mgk920]

Around here the rural unincorporated addresses are assigned by local building inspectors on county-wide E-911 grids, while what the 'city' name of the address is is at the discretion of the USPS. The postal city name bears very little correlation with any political boundaries (except in the urbanized incorporated areas) and is done solely for the ease of delivery service by the Post Office.

Also, the USPS can and does object to proposed new street names if they duplicate already existing ones in a particular postal 'city' area.

Mike

[Dan]

Where my parents lived, in the Town of Amherst, New York, the sign on the post office building read "Buffalo NY 14221", and most of their mail got addressed to either "Buffalo" or "Williamsville". Amherst and Hamburg, both suburbs of Buffalo, are notorious for having town neighborhood names as mailing addresses (Snyder, Eggertsville, Getzville, East Amherst, Woodlawn, Lake View etc.), just like in Queens in NYC. Some Amherst and Hamburg residents residents actually believe they live in some nonexistent "Village of Bowmansville" or "Village of Wanakah". My parents firmly believed they lived in the Village of Williamsville, which actually does exist, even when I showed them a Town of Amherst map that showed otherwise. It causes a lot of confusion, but it's "tradition". 500 years from now, people living near the intersection of what was Main Street and Harlem Road will be calling it "Snyder" centuries after the municipality's name changed to 上层中产阶级镇建在一片沼泽地.

When I worked in Florida, the majority of residents of the small town where I worked had the mailing address of an adjacent low-status municipality. We successfully petitioned the USPS to allow the legitimate use of our town's name with the underlying Zip code.