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Median Center of Population for the United States: 1880 to 2020 (2021)
- Ancalagon 3y agoDoes this include Puerto Rico?
- deciduously 3y agoPuerto Rico's population is around 3 million, less than a percent of the 331 million population of the US. I wouldn't expect more than a slight change to the graph either way.
- s1artibartfast 3y agoIt is quite far south so it would have a significant impact on the mean, although not the median
- aldonius 3y agoSouth, but potentially east a little too. (PR is further east than all but parts of Maine). Right now most of the Bay Area is barely to the south of the median, so I suspect the 2030 update won't change much there. As far as east-west goes it looks like it's in the middle of Chicago right now (which also helps explain why 2010-2020 didn't move that far west).
- s1artibartfast 3y agoI brought up the Bay Area in terms of the medium because someone moving from the Bay Area to Hawaii would have zero impact on the median population longitude. However, it would impact the mean population longitude
- aldonius 3y agoOh, I wasn't referring to your other comment. Just noting that since the Bay Area's pretty heavily populated, bringing in Puerto Rico (shifting the US median south by ~1.6 million people) takes the median from say Napa's latitude to, say Alameda's latitude (keeping in mind that there's also Louisville KY and other smaller non-SFBA towns in the same band of latitude).
- r00fus 3y agoI'm guessing it doesn't - as PR is unincorporated. However, census is used in all sorts of things aside from voting/representation, so who knows.
- flangola7 3y agoWhat does incorporation matter? It's American citizens on American soil.
- kens 3y agoThe computation uses the 50 states (or 48 conterminous states for calculations made prior to 1960) and the District of Columbia. Source: https://www2.census.gov/programs-surveys/decennial/2010/program-management/4-release/press-kit/center-of-population/centers-of-population-computation-documentation.pdf https://www2.census.gov/programs-surveys/decennial/2010/prog...
- AndrewKemendo 3y agoFollows the shape of the gulf coast from northwest FL to Mexico approximately which would track the southwesterly flow of people
- ks2048 3y agoI know there's a lot of reasons for this, but I think weather is one of the biggest. I wonder if that ever reverses from extreme heat. Is a full month of 110+ degrees having people reconsider Arizona?
- topspin 3y agoI went the opposite direction of that line several years ago. It's been high 70's and low 80's all summer. Two low 90 days so far. Last winter was mild as well. So yeah, that could happen. Lots of water here as well.
- psychlops 3y agoArizona is tax friendly to retirees allowing a more comfortable living on a fixed income. That can pay for a lot of air conditioning (or swamp coolers).
- bachmeier 3y agoAir conditioning changed everything: https://www.energy.gov/articles/history-air-conditioning https://www.energy.gov/articles/history-air-conditioning > Engineer Henry Galson went on to develop a more compact, inexpensive version of the window air conditioner and set up production lines for several manufacturers. By 1947, 43,000 of these systems were sold -- and, for the first time, homeowners could enjoy air conditioning without having to make expensive upgrades. > By the late 1960s, most new homes had central air conditioning, and window air conditioners were more affordable than ever, fueling population growth in hot-weather states like Arizona and Florida. Air conditioning is now in nearly 100 million American homes, representing 87 percent of all households, according to the Energy Information Administration.
- Eumenes 3y agoPeople are way more tolerant of extreme heat compared to cold
- bell-cot 3y agoYes...up to a point. And there's the similar/related issue of extreme drought. If the wells and pipes run dry, the local population density tends to plummet.
- ummonk 3y agoTechnically the spot on the opposite side of the earth is also a median right?
- 6gvONxR4sf7o 3y agoNope. https://en.wikipedia.org/wiki/Geometric_median https://en.wikipedia.org/wiki/Geometric_median
- ummonk 3y agoThanks. That's an elegant definition of median!
- aidenn0 3y agoYes because it's the intersection of a meridian and a parallel, which is two points anywhere except the poles.
- narcindin 3y agoLooks like the 2020 line is just east of Chicago and just north of the SFBA. The line can't move West or South too quickly as every additional minute represents so many people shifting from one side of the median to the other.
- Retric 3y agoNot just movement east west or north south but also births, deaths, immigration, and emigration. Also of note, the quadrants aren’t balanced. You could have 1x in the northwest, 2x in the northeast, 2x in the southwest, and 1x in the southeast.
- s1artibartfast 3y agoI'm not sure what median Center of population means. Mean would be the geographic center accounting for location. Is the median just the 50th percentile in latitude and longitude?
- lotsofpulp 3y agoI would guess it means 25% live in each quadrant of the map here: https://www2.census.gov/geo/maps/DC2020/PopCenter/CenterPop_Median_1880-2020.pdf https://www2.census.gov/geo/maps/DC2020/PopCenter/CenterPop_...
- cschmid 3y agoNot quite: half are on the left, and half are on the right of the vertical line; and half are on the bottom and half on the top of the horizontal line.
- bglazer 3y agoMake a list of lat/long for every person, pick the middle entries?
- sixstringtheory 3y agoSomeone else posted this link: https://en.wikipedia.org/wiki/Geometric_median https://en.wikipedia.org/wiki/Geometric_median It’s the point the that minimizes the distance to all the input points in Euclidean space.
- paxys 3y agoI'm going to guess this isn't what they actually mean. It's more likely just the spot where an equal number of people live left and right as well as above and below it.
- s1artibartfast 3y agoYou might be right, but I was more curious about what a technically accurate reading of the statement would mean.
- carapace 3y agoHmm... The "Dwight D. Eisenhower National System of Interstate and Defense Highways"? Started around 1956. https://en.wikipedia.org/wiki/Interstate_highway https://en.wikipedia.org/wiki/Interstate_highway
- paxys 3y agoWestward expansion never stopped.
- kens 3y agoThere is a lot of speculation here on what this means, so I looked it up. The median center is the point through which a north-south and an east-west line each divides the total population of the country in half. This is different from the "center of population", which is the balance point if you took an imaginary flat surface and put an identical weight on it for each person. These are both different from the geometric median. This document explains how the census bureau computed the values and has equations. There are complications since the earth is a sphere (as far as the census bureau is concerned): https://www2.census.gov/programs-surveys/decennial/2010/program-management/4-release/press-kit/center-of-population/centers-of-population-computation-documentation.pdf https://www2.census.gov/programs-surveys/decennial/2010/prog...
- nonethewiser 3y ago> which is the balance point if you took an imaginary flat surface and put an identical weight on it for each person. And with real weight for each person we'd see a center-point further south.
- desertrider12 3y ago> This is different from the "center of population", which is the balance point Does the difference only come from the earth curvature? I’m thinking if two lines each split the population in half, their unique intersection must also be the general balance point (for a flat surface anyway)
- function_seven 3y agoThe balance point would rarely also be on the north-south, east-west intersection. The only time that would happen is if the distance of each person was also equal on either side of your meridian and your latitude. In reality, the clumpiness of the populations on either side of your dividing lines are going to be different. You could have a dispersed population on the west side of the meridian, but a concentrated population far away on the east side of the meridian.
- MathMonkeyMan 3y ago
- biomcgary 3y agoI believe Washington DC was close to the median center at the founding of the US. I've often wondered about the effect on US government if the seat of the executive (white house), legislative (capitol), and judicial (supreme court) branches had to move to the median center after every census. We need something to reduce the influence of K street. Something to keep the lobbyists from getting too cozy would be nice.
- ke88y 3y ago> Something to keep the lobbyists from getting too cozy would be nice. That doesn't make much sense to me. The firms that rent office space on K Street don't have power because of the location of their office... it's the other way around: K Street real estate is rented out by those firms because of the street's proximity to power. Move the power center and the firms currently renting office space on K Street, DC, USA will instead rent out space on Blah Street, Middlepoint, USA. More-over, I don't know if moving the capitol of the country to the median point as defined in this article makes any sense either. It's one of those "literally everyone loses" propositions because "median" isn't "modal". If anything, it could make sense for the capital to be located at the midpoint by travel time. But it's all wildly impractical if you stop and think about. The amount of infrastructure alone would require decades of work. And states would have to surrender sovereignty over a big chunk of their (settled!) land. Etc.
- bobthepanda 3y agoThe midpoint by travel point mattered more in an era where travel across the country was measured in weeks or months. At this point the only people with difficult transport are those in rural communities that may lack air services, though to combat this somewhat Congress funds the Essential Air Service at hundreds of millions of dollars a year.
- ke88y 3y agoGood point. Again, the whole thing feels a bit silly. Not a huge fan of DC but not sure why you'd think moving the capitol would actually change anything about how politics works... I think this "move the capitol" thing is pushed by people who think "then DC would be accountable to small town America because it would be in small town America!" Which, LOL, no. That's not how it'd work at all. That small town would lose self rule, be developed into a mid-sized city, become completely divorced from its previous character, and nothing else would change other than building a big ass city in Small Town, IL for no particularly discernible reason. Which sets aside the fact that Small Town America already has an absurdly disproportionate amount of representation per human inhabitant.
- bmurray7jhu 3y agoMathematically rigorous definition of "median center of population": https://www2.census.gov/geo/pdfs/reference/cenpop2020/COP2020_documentation.pdf https://www2.census.gov/geo/pdfs/reference/cenpop2020/COP202...
- kepler1 3y agoAmazing how little distance it's moved. Maybe it should be obesity-weighted to show it better. Oh wait, that would not help. Maybe that's why it hasn't moved much...
- JamesSwift 3y agoIt will be interesting to see if this line starts moving back north if (when?) summers and heat in general continue to be this brutal. I'm a native Floridian and love it here, but I'll be damned if I haven't given thought to moving back somewhere a little more temperate after these past 2-3 months.
- autoexec 3y agoThat's my guess. People will increasingly be moving away from the coasts due to flooding and storms and moving north to avoid the heat and other hazards (insects, diseases, etc) that are moving north and spreading.
- fooker 3y agoCoastal real estate prices don't seem to match this prediction.
- autoexec 3y agoIt does in some places (https://www.npr.org/2020/10/15/924239753/is-the-risk-of-sea-level-rise-affecting-florida-home-prices-a-new-study-says-yes https://www.npr.org/2020/10/15/924239753/is-the-risk-of-sea-...) but I suspect it'll get much worse as climate change increases the frequency and intensity of storms and tax payers get more and more fed up with paying to repair the damage again and again in flood prone areas. (https://www.pewtrusts.org/en/research-and-analysis/articles/2020/10/01/repeatedly-flooded-properties-will-continue-to-cost-taxpayers-billions-of-dollars https://www.pewtrusts.org/en/research-and-analysis/articles/...). California will likely be a hold-out much longer than other states. Earthquakes, wildfires, rolling blackouts, water shortages/restrictions, high unemployment, insane housing costs, high cost of living, and the worst traffic in the country haven't been enough to keep people away from California.
- fooker 3y agoFlorida is not affected by this yet, home prices have steadily increased except for a sell off during the pandemic. https://fred.stlouisfed.org/series/FLSTHPI https://fred.stlouisfed.org/series/FLSTHPI
- tfehring 3y agoI wonder what the median distance from the ocean is and how that's changed over time.
- deleted 3y ago[deleted]
- HDMI_Cable 3y agoA couple interesting things here: first, what was that loop circa 1890-1940? I can't think of any major trends that would cause a westward and northward shift of the population except for the industrialization and de-industrialization of the midwest, though in my mind, de-industrialization (and thus population shifts) only occured in the 1980s or so. Second, why did it shift so drastically in the 1970s? You would expect a massive shift in the 1840s and 1850s with the Oregon Trail and Manifest Destiny, but I can't think of any shift in US history that would cause that large. Third, I'm curious where this dot would be during the Revolution (probably somewhere in North Carolina, I would guess), or during Columbus.
- Leary 3y ago1. a combination of the continuing growth of the West and the Great Migration https://en.wikipedia.org/wiki/Great_Migration_(African_American) https://en.wikipedia.org/wiki/Great_Migration_(African_Ameri...
- jmopp 3y agoConsider the Great Migration of African-Americans from the Jim Crow south to the industrialising Midwest. 1930-1940 is also the height of the Great Depression and the Dust Bowl, so people would be migrating from the Plains areas down to California for better opportunities. With regards to the big shift in the 70s, the first thing that comes to mind is widely-available air conditioning making the interior of the southwest more habitable
- Pxtl 3y ago[flagged]
- cout 3y agoI'm surprised to see a data point for the 1890 census given that much of the records were destroyed in a fire. https://www.census.gov/history/www/genealogy/decennial_census_records/availability_of_1890_census.html https://www.census.gov/history/www/genealogy/decennial_censu...
- blitzar 3y agoAmerica is making a run for the border.