In recent U.S. presidential elections, rural counties have tended to vote heavily for the Republican candidates. As a result, most of the United States is shaded red on county-level electoral maps. Most of the low-population counties that do support Democratic candidates fall into one of several categories. In some cases the explanation is clearly demographic; the heavily African-American belt stretching from southeastern Virginia to western Mississippi, the heavily Hispanic areas of northern New Mexico and southern Texas, and the scattered Native American counties in the northern Great Plains and the Southwest have long been Democratic strongholds. Location also plays a role, as rural counties in New England and on the Pacific Coast that are closely connected with nearby metropolitan areas also tend to support Democrats. Most of the other seemingly anomalous blue rural counties can usually be explained by their specific characteristics, such as the presence of a major ski resort (Blaine County, Idaho), a local economy based (or recently based) on unionized mining (Silver Bow County, Montana), or the existence of a large college (Athens County, Ohio).

One large block of largely rural, Democratic-voting territory, however, does not fit into any of these categories. In what might be called the “Upper Mississippi River Valley Anomaly,” one finds a substantial cluster of mostly agricultural, deeply religious, heavily Caucasian “blue” counties. In this area focused on southwestern Wisconsin, southeastern Minnesota, eastern Iowa, and northwestern Illinois, almost all counties opted for Barack Obama. A few counties in western Minnesota and in the eastern Dakotas, located just outside this contiguous zone, also exhibit the same pattern.

The voting behavior in few of the counties in this zone can be explained by their particular characteristics. Dark-blue Dane county in Wisconsin, for example, is the site of the main campus of the state university, and the same is true in regard to Johnson County in Iowa. Strongly Democratic Mower County in Minnesota, in contrast, contains a massive meatpacking facility, and is therefore a labor stronghold. Most of the counties in this area, however, are typical farming communities, dominated by Whites and slowly losing population. Consider, for example, Mitchell County Iowa, population 10,776 (having dropped from 14,121 in 1940). As the Wikipedia article on the county notes, “Mitchell County was the whitest county in the country, at 99.27%, to vote for Barack Obama in the 2008 Presidential election. Obama garnered 56% of the vote, while John McCain received 44%.” Obama’s margin over Mitt Romney in 2012 was not so wide, but the President still took Mitchell County with room to spare.

The Upper Mississippi River Valley Anomaly dates back roughly a dozen years. In the early 1980s, the area was heavily Republican, overwhelmingly supporting Ronald Reagan. In the 1990s, many counties in the region turned to Democratic Bill Clinton, but so too did many other parts of the country with similar demographic and economic characteristics. By 2000, however, a distinct atypical zone had emerged in this region. As result, Iowa in particular has become a divided state, red in the west and blue in the east. The same spatial divide can be seen in primary elections; Republicans in western Iowa, for example, were less inclined to support Romney’s nomination than those in the east, favoring instead the more conservative candidates such as Rick Santorum and Rick Perry.

I t is difficult to find correlations that might help explain this phenomenon. As the paired political and demographic maps of Iowa indicate, more of the blue and light-red counties in the state have larger cities and towns than the deep-red counties, but the linkage is not strong. Nor can the Iowa vote in general be explained on the basis of religion, as the state’s main religious divide separates the south from the north, not the east from the west. (As can be seen in the maps, southern Iowa has lower rates of church attendance and a higher proportion of Methodists than the deeply religious, strongly Lutheran north.) Religion does seem to be a factor, however, in the strongly Republican northwestern corner of Iowa, where three counties are dominated by members of the historically Calvinist Reformed Church.

Similarly, factors that might help explain the existence of the larger Upper Mississippi River Valley Anomaly are difficult to locate. The agricultural foundations of the local economies do not seem to play a role, as the “anomalous zone” includes part of the Corn Belt and part of the Midwestern dairy belt. Issues of ethnic heritage also seem to be minor. The zone in question is heavily German, but so too are surrounding areas. Much the same can be said in regard to Norwegian background; many of the farming counties that have been voting for Democratic candidates in recent elections were heavily settled by Norwegians, but so too were a number of decidedly Republican counties in North Dakota.

Minnesota is also the key site of another intriguing anomaly in U.S. electoral geography. Over the past few decades, the state as a whole has been solidly blue, not opting for a Republican candidate since Richard Nixon’s landslide victory in 1972. Yet a number of Republican strategists thought that Romney had a good chance of taking Minnesota in 2012. In the end, Obama won the state by more than a seven percent margin, but that margin was still relatively thin when compared with those found in other solidly blue states.

To the extent that Minnesota might be regarded as a purple-trending swing state, the answer is located in suburbs. In the northeastern and Pacific Coast states, the suburbs have switched in the past three decades from Republican to Democratic bastions. As conservative historian Vincent Cannato notes, “The GOP needs to run better in affluent suburban counties. If the party of business and economic growth can’t do well among the most prosperous and economically vibrant parts of the nation, then something is seriously wrong.” But in Minnesota, and in neighboring Wisconsin as well, the suburbs remain red. In fact, they have moved in the Republican direction over the past few decades. Consider, for example, the paired maps of the greater Minneapolis/St. Paul metropolitan area posted here. In 1980, when Ronald Reagan took 489 out of 538 electoral votes nationally, Jimmy Carter took almost the entire metro area. In 2012, however, Obama lost most of the suburban counties, while easily wining the mostly urban counties of Hennepin (Minneapolis) and Ramsey (St. Paul). The northern suburbs of Minneapolis and St. Paul are represented in Congress by Michele Bachmann, one of the most conservative members of the House of Representatives. Bachmann won reelection this year, although narrowly.

When examined over the past three decades, Minnesota thus exhibits dual anomalies, with affluent suburban counties trending Republican and the rural, farming counties in the southeast (and to some extent in the far west) trending Democratic. (The mining and logging counties of the northeast have remained in the Democratic camp over this period.) Such patterns are difficult to explain. If any readers have any ideas, I would love to see them.