30 December 2019 — 1724 mst
Don’t bet the ranch on a 2nd seat
U.S. Census Bureau releases 2019 population estimates —
Daily Kos & EDS predict MT may get 2nd U.S. House seat
The U.S. Census Bureau today released its population estimates for 2019 (net-est2019-01.xlsx). The bureau estimates that Montana’s population as of 1 July 2019 was 1,068,778, an increase of eight percent from 2010. The nation’s growth rate for 2010–2019 was six percent.
Assuming the U.S. House remains fixed at 435 members (Congress can increase that number to approximately 10,900), Montana, by growing slightly faster than the nation, may gain a second seat in the U.S. House of Representatives.
At the Daily Kos blog, Stephen Wolf predicts a one seat gain for Montana. Election Data Services’ apportionment study for 2019 was published a few minutes ago with the headline “Montana Gains California’s seat.” In 2018, EDS predicted a one seat gain for Montana.
These predictions come with caveats. A second seat for Montana is not a slam dunk. We’re right on the bubble. Reapportionment will be based on the actual count in 2020, and there could be surprises.
The state of Montana is just barely able to reverse previous decades of population shifts when it went from two seats down to one in 1990. For 2020 the state is projected to go back to having two seats, but that gain of a second seat is because the state occupies the dubious distinction of obtaining seat #435, the last one to be apportioned. Election Data Services calculations show Montana getting that additional seat by only between 2,402 and 4,163 people to spare; a very close margin.
Mathematics of apportionment. The Census Bureau calculates the reapportionment allocation using the method of equal proportions, also known as the Huntington-Hill method. For a lucid and entertaining analysis of the major methods of apportionment, see Fair Representation: Meeting the Ideal of One Man, One vote (Balinski and Young, 2001), and The History of Congressional Apportionment (PDF) by Charles Biles (2017).
County level estimates for 2019 have not, as far as I can determine, been released.