My Democratic friends often complain that the Republicans have gerrymandered us out of several seats in the South Dakota Legislature. Such complaints return my attention to a topic of frequent interest here: redistricting.

This is your state's Legislative map:

South Dakota Legislative Districts, in effect for elections from 2012 to 2020.

South Dakota Legislative Districts, in effect for elections from 2012 to 2020. (Image from Brian Olson, BDistricting.com. Click image to view official interactive map!)

This is your state's Legislative map on math:

Possible equipopulational, optimally compact legislative districts, mapped by Brian Olson, BDistricting.com.

Possible equipopulational, optimally compact legislative boundaries for 35 Senate districts, mapped by Brian Olson, BDistricting.com. (Click for original data and bigger image!)

Brian Olson of BDistricting.com mapped out legislative districts for every state based strictly on 2010 Census data and distance. His maps ignore local boundaries and political affiliations. His math produces hexagonal districts that make South Dakota look like a state of little Frances (O! that we could make it so!).

Interestingly, this arrangement reduces the average voter distance from district center by just a tenth of a mile, to 20.75 miles. No matter how you slice South Dakota, districts from the James River Valley west are going to cover a lot of ground.

Break our 35 districts into single-member districts for our House, and the map produces some more amusing results:

SDLeg-70bypop

Possible equipopulational, optimally compact legislative boundaries for 70 single-member House districts, mapped by Brian Olson, BDistricting.com. (Click for original data and bigger image!)

New districts bubble up along I-90 on the northeast edge of the Black Hills and from Plankinton to Sioux Falls. These districts again reflect the beautiful math that ignores political affiliation, but they also ignore the court-ordered boundaries that support fair American Indian representation under the Voting Rights Act.

Would shifting district boundaries by Olson's politically blind math make a difference in the partisan make-up of the Legislature? I welcome your guesses on that count. But consider these numbers:

  1. 66% of the votes cast in 2014 for State Senate went to Republicans. 34% went to Democrats.
  2. Look only at contested races (that eliminates 13 Republicans and 5 Democrats), and you find GOP Senate candidates drawing 58% of the vote, Dems 42%.
  3. The incoming Senate is 77% Republican, 23% Democrat.

We should be careful what we wish for: if pure mathematical redistricting also happened to perfectly distribute Republicans and Democrats, then this year's election could have resulted in 66%–34% GOP–Dem splits in every district, meaning the whole Senate would have been Republican. Uff da—imagine that!

Related Reading: This May 2014 Vox article shows what Congressional districts would look like if we ignored state boundaries and used the shortest split-line algorithm:

Split-line Congressional districts, produced by Warren Smith and Jan Kok, RangeVoting.org.

Split-line Congressional districts, produced by Warren Smith and Jan Kok, RangeVoting.org. (Click to embiggen!)

Aberdeen, Huron, and Watertown would share a Representative with Fargo, Jamestown, and Devil's Lake. Pierre and West River would be in with Bismarck, Minot, and the Bakken oil fields. Mitchell, Yankton, Vermillion, and Dakota Dunes would go with Sioux City, Norfolk, and Grand Island. Sioux Falls would come out as the population hub of a quadrilateral consisting mostly of southwestern Minnesota and northwestern Iowa.