There are some places in US, that contain "MO" in their names. For example, Columbia, MO; Kirkwood, MO; Saint Louis, MO. So, what does MO mean?

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    All places in the US end in a two-letter code for the state. It's just usually they are much more obviously related to the name of the state. Unfortunately, 8 states start with M and MI already got used for Michigan. Jan 24, 2013 at 20:45
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    Canada's provinces and territories have similar abbreviations, too, and the USPS and Canada Post have coordinated to avoid ambiguity, which is why NB is New Brunswick and NE is Nebraska. May 18, 2018 at 16:34
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    @JimMacKenzie nonetheless, I can never escape confusion when I see Ontario, CA. Nebraska actually was NB from 1963 to 1969, if the Wikipedia article is to be believed. NL also trips me up routinely, since I lived in Amsterdam when Newfoundland and Labrador received its current name.
    – phoog
    May 19, 2018 at 4:02

2 Answers 2


It's the two-letter code of the state.

MO is Missouri.

List of U.S. state abbreviations - Wikipedia

You can learn them with this geographical game of States of USA or text game of states abbreviations.


The state abbreviation (such as MO) is sometimes required because quite often there is more than one city with the same name in the US. There is a "Portland" in Maine and one in Oregon; Kansas City, Missouri and Kansas City, Kansas (same city, but the state line runs across the city), and almost each state has it's own "Springfield".

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    @Flimzy It is extremely common; more uncommon than only one place in the US having the name. There's a Los Angeles, TX. There are five places named Philadelphia not in PA. New Chicago, CA used to just be Chicago, CA. I've actually checked a few, and so far only NYC seems to be the only unique city name in the US.
    – Andy
    Jul 25, 2017 at 0:08
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    @Flimzy "I must disagree with this reasoning; although it's true there are often multiple cities with the same name in the U.S., state names abbreviations are used almost without exception, even when there is only one." My point is that there is almost never "only one" city with the name, so the reasoning in the answer makes 100% sense, contrary to the opinion in your comment.
    – Andy
    Jul 25, 2017 at 14:24
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    @Andy You said the only unique city name was New York, and I found you another. May 18, 2018 at 20:19
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    @phoog That's fine, but whether a particular city name is unique across all 50 states is not really the point. The point is that there are enough that are not unique that the state needs to be explicit, as in the answer.
    – Andy
    May 21, 2018 at 1:17
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    @phoog i disagree, especially in the context of travel where a visitor may not be familiar with the US, which seems to be what prompted this question in the first place.
    – Andy
    May 21, 2018 at 10:48

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