While the US Census (which was last taken on April 1, 2010) is formally conducted every 10 years, the Census Bureau periodically posts population estimates for each county/parish. Earlier today, July 1, 2016 population estimates were released for all of Louisiana’s 64 parishes. What do these population estimates tell us ?

While Louisiana’s population growth has for decades been less than the national rate of growth, it nevertheless has been slow but steady since 2010. It’s current (July 1, 2016) estimated population was 4,681,666, which is a 3.2% increase since the 2010 Census (the national rate of growth was 4.7%).

Assuming that the current rate of population growth were to continue until the 2020 Census, Louisiana would grow 5.2% – a decline from last year’s projected 5.8% population growth, and is likely a byproduct of a slowdown in the “oil patch.” Still, this is a rate of population growth the state has not seen since the 1970s. Plus, this rate of growth would likely allow it to keep its six Congressional seats in 2020.

When we look at individual parishes, the story is similar to what it was after the 2015 population estimates: 35 out of 64 parishes lost population. Compared to 2015, Cameron Parish went from losing to gaining population.

Population Change between 2010-2015 (Red=gained population, Blue=lost population)

There are five takeaways from the Census estimates: (1) the massive population losses in Orleans and Saint Bernard Parishes after Hurricane Katrina in 2005 are more and more a thing of the past, as those two parishes have remained the fastest growing in the state, with double digit rates of population increase (27% in St Bernard and 14% in Orleans) between 2010 and 2016, (2) population growth remains the strongest in the “10/12 corridor” (i.e., those parishes along I-10 or I-12), with 6% population growth between 2010 and 2016, (3) population growth along the I-20 corridor remains modest: only a 1% change in population between 2010 and 2016, and (4) there was no population growth along the I-49 corridor, and (5) parishes not along an interstate highway showed a 1% population loss.

Regions (Green=1-10/12 corridor, Red=I-49 corridor, Blue=I-20 corridor)

These population estimates (and the actual counts, which will be released after the 2020 census) are important because a variety of government bodies – from the U.S. House delegation to local governmental bodies – are geographically apportioned on the basis of its Census population every 10 years. And given that the next legislative reapportionment will be conducted before the 2023 statewide elections, there will likely be some statewide impact.

Such impact is likely to be visible at the state house level because population changes more substantially impact state house more than state senate districts. And if we project 2010-2016 population changes ahead to 2020, it looks like Orleans and St Bernard Parishes combined will “recapture” one of the four state House seats eliminated during the 2011 reapportionment. Furthermore, continued robust population growth along I-10/12 between Lafayette and the Pearl River means that a new district is likely to be created somewhere in Ascension, Livingston, Tangipahoa, or St Tammany Parishes.

Since the state House is fixed at 105 seats, those two gained seats have to be offset somewhere. Currently, it looks like Caddo Parish could lose a seat, while another seat would come from one of the parishes not along an Interstate highway. However, it’s important to emphasize that these are estimates – nothing is final until the official April 1, 2020 Census count. Furthermore, internal legislative politics can and will play a large part in determining the specific seats that are added or eliminated.