South Dakota ZIP Codes: What Yours Really Means

Did you know that there are nearly 42,000 ZIP Codes in the United States? That's a heck of a lot, especially since I can only remember three.

The one from my hometown because it was pounded into me in elementary school, because addressing an envelope was apparently a chief skill to learn back in the 80s, along with cursive and giant parachute skills.

The second one I remember is from my college town. This one is burned into my brain because I started college in the age of filling out lots and lots of paper forms.

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How Many ZIP Codes Does South Dakota Have? More Than You’d Think

The third one is the Sioux Falls ZIP Code I have now. I've lived in the same Sioux Falls ZIP for over a decade. This one is branded on my brain because it's the one I had to pound into MY kids' heads. Ahh, the circle of life.

Sioux Falls has 15 ZIP Codes assigned to it in three categories. There are seven standard ZIPs, 57103-57108. Four of the ZIPs are for PO Boxes across the area: 57101, 57109, 57117, and 57118.

The last four ZIP Codes are unique codes for organizations or buildings that receive a large volume of mail. Like 57197 is the ZIP Code for Augustana University in Sioux Falls.

The ZIP in ZIP Code is an acronym for 'Zone Improvement Plan.'

The United States started using postal codes to sort mail during WW2. Then they were used in 124 large cities. Then, in 1963, the ZIP Code as we know it came into being.

The country was getting too large, and the volume of mail was too great to reliably sort it based on street address alone. In 1983, the U.S. Postal Service introduced the ZIP+4 codes, which narrow down the delivery area even ZIP Code.

The Meaning of the ZIP Code Numbers

The first digit of a ZIP Code refers to a group of states; for example, South Dakota, North Dakota, Minnesota, Wisconsin, Iowa, and Montana ZIP Codes all start with a '5'.

The second and third numbers represent a region within the first one that is associated with a mail distribution facility. All ZIP Codes in South Dakota. Then the next numbers correspond with even smaller areas within the region. The fourth and fifth numbers represent towns or areas of a city.

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How ZIP  Codes are Determined

New ZIP Codes are created based on population growth and input from local Postal officials. ZIP Codes can be retired as well if an area loses a lot of people.

The Largest ZIP Codes in South Dakota

With a population nearing one million, South Dakota has 375 ZIP Codes as of 2025. I wouldn't be surprised if we add more over the next few decades.

The South Dakota ZIP CODES with the most people in them all correspond to the state's largest urban areas. There are a few in the western part of the state that cover a fairly large area, but have smaller populations.