Where Are All the New South Dakotans Coming From?
South Dakota’s population continues to rise. The significant state population growth seen in 2020-22, fueled largely by migration from the rest of the US, continued into 2023 but at a lower rate. The Census Bureau-estimated South Dakota state population of 919,318 represented growth of 9,449 over 2022 (Table 1), less than the exceptional prior year, but faster than the year before that. Net domestic migration (inmigration – outmigration) dropped from 8,424 in 2021-2022 to 4,812 in 2022-2023. The most recent flow was also lower than the 2020-2021 flow. Although lower than the prior two years, the 2022-2023 flow was still higher than any other year since 2000. Births were about the same as prior years. Deaths declined significantly following the peak Covid years, but they were still higher than any other year since 2000. Combining births and deaths, natural increase was about 2,800, higher than both prior years.
Thirty-eight of South Dakota’s counties experienced population growth between 2022 and 2023, one experienced no change, and twenty-seven lost population. The vast majority of the state’s growth occurred in four counties. Minnehaha added about 3,100 residents, roughly a third of the state’s total growth. Lincoln added about 2,200, a little less than a quarter of state growth, and Pennington and Lawrence added about 1,600 and 800, respectively, together accounting for another quarter of state growth. When the next group of ten counties with growth between 485 (Brookings) and 92 (Lake) are added in, the total of the top fourteen counties is equal to the overall state growth. As a group, the remaining fifty-two counties broke even, with the largest loss experienced in Brown (-168) and the largest gain in Butte (+73). The spatial pattern (Figure 1) clearly shows the western and southeastern growth, with additional growth in other eastern counties. The most notable declines were clustered in the north central and southwest.
Scaling the population change by initial population, South Dakota’s population grew by about one percent between 2022 and 2023. Lincoln and Lawrence led the counties with growth rates of about three percent. No other counties grew at more than a two percent rate, while many, including Minnehaha, Pennington, and Brookings, had growth rates of around 1.5 percent. Ziebach experienced the largest decline at about three percent, while McPherson, Jones, and Jackson had losses of about two percent or larger. When viewed in percentage terms, the spatial pattern (Figure 2) evident in the growth numbers is accentuated by the significant losses in the southwestern and north central areas.
Total population changes result from natural increase (births – deaths) and net migration, both domestic and international. At the state level, births increased the population by 1.25%, above the national figure of 1.2%. The highest county rates were well above the state value, exceeding two percent in Buffalo, Corson, Dewey, Hamlin, Jackson, and Todd, most of which have majority Native American populations. This is clearly seen in the map (Figure 3) of birth rates. The lowest birth rates (at or below 0.85%) were found in Custer, Day, Fall River, Lawrence, McPherson, and Sully.
Combining births and deaths into natural increase, we find a state rate of 0.31%, indicating that independent of migration movements the state population has a natural momentum of growth. Hamlin, with its exceptional birth rate, stood out with a natural increase rate more than a full percentage point higher than the state, while Clark, Hardin, Jackson, Lincoln, Lyman, Minnehaha, and Todd had rates roughly double the state’s or higher. There is not a clear regional pattern (Figure 5) of rates of natural increase. Among the twenty-seven counties that had negative natural increase (deaths exceeded births) Hyde (-1.19%), Fall River (-1%), and McPherson (-0.71%) had the lowest rates.
Population changes from migration in South Dakota were generally larger than natural increase. The overall net migration rate of 0.73% is more than double the natural increase, with a split of 0.53% due to domestic migration and 0.2% due to international migration. Given their stronger relative importance, county migration flows follow a pattern similar to that of total population growth. Minnehaha and Lincoln had the largest total increases (1700-1800 each) from net migration, with Lincoln’s growth almost entirely domestic migration and Minnehaha’s about 2-to-1 domestic versus international. Pennington and Lawrence’s net migrations of 1,278 and 879, respectively, were almost entirely due to domestic migration. Brookings was the only other county with more than 200 net migrants, a total driven mostly by international migration. Brown’s net outmigration exceeded 200, while Todd and Oglala Lakota were next with net outflows of more than 100.
When scaled as percentages of the initial 2022 population, Lawrence’s 3.23% and Lincoln’s 2.89% are far higher than any other counties. Turner, Buffalo, and Douglas are the only other counties with migration percentages over 1.5%. The large numerical increases amount to much more modest percentage increases in Minnehaha (0.87%) and Pennington (1.09%). Ziebach (-3.26%) and Jackson (-2.72%) had the largest percentage population decreases due to migration, with Harding, Jones, and McPherson experiencing losses between 1.5 and 2%. Beadle, Brookings, Grant, and Sully had the highest percentage changes due to international migration, with Beadle (257) and Brookings (193) being the only counties other than Minnehaha with more than 100 international immigrants. The maps of domestic and international migration illustrate the relative domestic migration (Figure 6) success of the southeastern and western counties along with the clear losses in the south central and north central regions. The international migration percentage map (Figure 7) captures Beadle as the lone county with a substantial percentage. Many counties had no or very little international migration.
The nature of domestic migration can be further investigated through the IRS annual data that reflects all paired flows between counties of twenty or more tax returns, including in-state and out-of-state numbers for most counties. The suppression and limited coverage (about eighty percent coverage) unfortunately create a significant limitation for most South Dakota counties, but the remaining data helps illustrate interesting cases of in-state versus out-of-state migration and particular county-to-county flows. Unfortunately, the IRS data release, which is one of the major sources for the Census Bureau estimates, is released publicly only after a longer lag, so the IRS data summarized below is for 2021-2022. The numbers are still sufficient to analyze spatial interactions among counties.
For example, the Minnehaha data (Table 2) reveal that, after the large inflow from neighboring Lincoln (2516) and from Brookings and Pennington (about 200 each), the next largest sources are Hennepin (Minneapolis) and Maricopa (Phoenix) at 150-175 migrants. Seven additional South Dakota counties sent at least 100 migrants, along with Omaha and Sioux City counties, San Diego, and nearby Rock County, MN. The remaining group is composed mostly of out-of-state counties. When all sources are considered together, Minnehaha’s 11,859 domestic inmigrants were split about 60-40 out-of-state over in-state.
Most of the counties sending inmigrants also received outmigrants from Sioux Falls. Most prominent again is Lincoln County, which received almost 800 more Minnehaha residents than it lost. No other county had anywhere near such an imbalance with Minnehaha. The next largest imbalance is another neighboring county, Turner (-103), which also received net inmigration relative to Minnehaha, as did Lake (-53). The next set of receiving counties with one hundred or more migrants were mostly among the larger sending group with the interesting addition of Cass (Fargo), ND, and Polk (Des Moines), IA. Those counties in the table with a ‘d’ designation for suppression most likely received outmigrants of less than the twenty-return (typically about forty migrants) threshold necessary for reporting. They would be included in the ‘other’ categories at the bottom of the table
The net flows relative to Minnehaha are also quite interesting. Minnehaha had a net outflow with the rest of the state, but after one accounts for the large net outflow to Lincoln and to Turner and Lake, Minnehaha had a net inflow of 504 from other South Dakota counties. Some of these are evident in the individual table entries for Brookings (34), Pennington (29), Davison (68), Clay (61), Codington(58), Yankton (33), Hughes (63), and Brown (59). A few smaller net inflows and a few net outflows, along with the net inflow of eighty from counties not individually identified, completes the interaction between Minnehaha and the remainder of the state. A general summary is that Minnehaha has net outmigration to nearby counties, a significant net inmigration from the next population tier of counties, and smaller net inmigration relative to lower population counties. Overall, Minnehaha had net outmigration of 440 residents to other South Dakota counties.
South Dakota had net inmigration of 1,556 from other states. No single net flow exceeded one hundred migrants. The largest known net inflows were from San Diego, Los Angeles, and Woodbury (Sioux City), although many counties had insufficient outflow numbers to report, so net migration could not be computed. The largest net outflows were to the aforementioned Polk (IA) and Cass (ND) counties and Dakota County in suburban Minneapolis-St. Paul. Minnehaha did have small net inmigration from the central counties of the Twin Cities, but there is no clear total exchange imbalance between the metropolitan areas. While there is slight net outflow to neighboring Rock (MN) which fits the in-state trend of loss to bordering counties, there are net inflows from Nobles (48) and Pipestone (17) counties in Minnesota. The net inflow from Woodbury (IA) is also present in Sioux (IA), but Lyon (IA), the closest, has a slight net ouflow. There is a rough balance relative to the Omaha-Lincoln portion of Nebraska. There appears to be a slight net outflow to Arizona counties, no clear tendency relative to Colorado counties, and a pronounced net inflow from the known California counties. The residual flows to and from counties aggregated together indicate large positive net inflows from other Western and Midwestern states, a smaller net inflow from Northeastern states, and a small net outflow to Southern states.
No other county approaches the same level of detail as Minnehaha, especially related to out-of-state migration. The reported data document that Pennington had net out-of-state inmigration of over 2,000, while Lawrence and Lincoln had 949 and 805, respectively. Custer, Fall River, and Meade each had net inflows of about 200, while Union, Yankton, and Codington had net flows of over 100. Brown reported a net outflow of about 200.
In-state migration was reported much more reliably, with only eight counties missing either in- or outmigration. As shown in Figure 8, Minnehaha and Lincoln stand out as the extremes, due partly to the large movement between the counties favoring Lincoln. Beyond the Minnehaha net inflow, Lincoln has an additional net inflow of about 300, still the largest in the state by a wide margin. Meade (142) is the only other county with a net inflow over 100, and Brookings is next with a net inflow of 90. Several counties had net in-state ouflows, led by Pennington (-142), Davison (-138, much of it to Minnehaha and Lincoln), Brown (-127), and Spink (-112).
Pulling together the various migration flows and natural increase, keeping in mind that the IRS data is from a year prior to the Census estimate, a more complete story of population change emerges. Growth in the state is dominated by only four counties. Minnehaha continues to grow through net migration with other states and international immigration along with strong natural increase. While it is losing population to surrounding ‘suburban’ counties, it maintains positive net inmigration with the rest of the state. Lincoln continues its strong growth with a combination of strong natural increase and positive net migration both in- and out-of-state. Pennington has only average natural increase and negative net migration within the state but very strong positive net migration relative to other states. Lawrence also has very strong positive net migration with other states sufficient to outweigh negative natural increase. Brookings and Codington counties both experience positive net migration and moderate natural increase. Yankton, Davison, and Beadle experienced slower growth, with Beadle’s attributed to sizeable international migration. Among other more populous counties, Brown and Hughes have experienced population declines due to low natural increase insufficient to counter net outmigration. Many southwestern and north central counties are similarly experiencing enough outmigration to more than counter generally positive natural increase.
Sources
Annual and Cumulative Estimates of the Components of Resident Population Change for Counties in South Dakota: April 1, 2020 to July 1, 2023 (CO-EST2023-COMP-46), U.S. Census Bureau, Population Division, March 2024.
IRS migration statistics, based on IRS Individual Master File, Statistics of Income, June 2024.