Optimum Population Density

I have used the term “optimum population density” quite a bit, but what exactly does that mean and what is the optimum population density for the United States?  It’s a really tough question to answer. 

To me, an optimum population density is attained when the following conditions are met:

  1. A large nation – certainly one the size of the United States – is self-sufficient in natural resources.  Now, obviously, no country can be self-sufficient in terms of each and every resource, since God has chosen to concentrate various resources in different areas scattered around the world.  For example, in spite of our size, the U.S. can’t be self-sufficient in providing our own coffee and bananas, because none of our geographic area extends into the tropics.  However, we can be self-sufficient in natural resources overall by trading what we have in excess for what we don’t.  If the dollar value of those exchanges is in balance, then we’re self-sufficient.
  2. We have sufficient labor to provide all of the products and services that we need to maintain a high standard of living.  This includes labor to man our factories, plant and harvest our crops, provide services, staff our governments, man our military, etc. 
  3. At the same time, we need to maintain our work force in a state of full employment.  Here I’m talking about true “full employment,” in which everyone is able to work as much as they want to support themselves at a standard of living that they’re comfortable maintaining.  In fact, it’s beneficial to maintain a supply of labor that is slightly below the level of demand in order to drive improvement in productivity. 
  4. Finally, the population cannot exceed the earth’s “carrying capacity” in terms of our effect on the environment.  That is, it cannot exceed the level at which the environment is able to absorb and break down our wastes.  This final point may be the most difficult to quantify.

It would be a very interesting exercise, one that the government should undertake, to load these parameters into a computer program and see what comes out.  It would probably yield an algorithm that would require a mainframe computer to crunch.  Factors 3 and 4 above would require knowing exactly how the per capita consumption of every product and service is affected by population density in accordance with the theory I’ve presented in Five Short Blasts.  A computer would probably have to run trial-and-error scenarios, assuming a certain population and then determining the effect upon consumption and the corresponding effect upon the demand for labor.  I think this would be a truly fascinating exercise, one that I’m surprised hasn’t yet been attempted by the world of academia.

But what does my gut tell me?  Well, it’s been decades since we were energy sufficient, but we were at one time, when our population was about half of what it is now.  And, at that same time, despite what the Labor Department’s official “unemployment rate” says, we were much closer to “full employment.”  Incomes were high, health care was affordable and pensions were secure.  Good jobs were plentiful.  And, although pollution was a problem in those days, it wouldn’t have been if environmental control technologies in use today were available then. 

So, my gut tells me that a population density of about 40 people per square mile, about half of today’s level, would be about right.  I came across an interesting microcosm just a couple of days ago that seems to lend support to this level.  I’ve been reading Fair Wind & Plenty of It, a chronicle of a modern-day round-the-world voyage on a square rigger brigantine ship, by Rigel Crockett, one of the ship’s crew.  In Chapter 23 he tells of the ship’s stop at Palmerston Island, a tiny one-square-mile patch of land in the middle of the Pacific Ocean, settled by one man, William Marsters, and his three wives in 1863.  Mr. Crockett observes that:

With William Marsters as that island’s strict autocrat, the family established a tribe that grew to one hundred, shrunk to thirty, and today hovered at forty souls, still living with remarkable self-reliance.

Forty souls on a one-square mile island in the middle of nowhere, completely self-reliant.  That’s exactly the population density – about 40 people per square mile – about half of today’s level of 83 people per square mile – that my gut says is about right for a much bigger land – the United States – and perhaps for the world as a whole. 




6 Responses to Optimum Population Density

  1. Julie Webster says:

    Hi, In response to your anecdote re Palmerston Island, I acted as a teacher there, last year for three months – the people are not self reliant, they are very much reliant on passing yachts, during the season, and the island freighter which offers a very spasmodic service anytime between three month five month intervals. There is one telephone for which they use to phone Rarotonga to order supplies for when a passing yacht calls, there are no shops. They all have television sets which they use to watch DVD’s supplied by the generosity of passing yachts and fresh fruit and vegies becomes rare after the yachting season.

    The only food they grow is taro, coconuts by the thousands, and the odd vegetable. The soil is mainly coral with only a smattering of earth provided by the tamanu trees which some sould had the foresight to plant many years ago.

    The people of Palmerston’s only cash income is from catching and selling fish to Rarotonga and a very few “government” jobs which have been made to give the population (when I was there of 60) some form of employment.

    The school’s population was 24, aged between 5 and 16 years of age, but I believe today the school roll numbers 14.

    Saying all this the people of the island are the most hospitable one can hope to encounter anywhere in the world and I look forward to returning some of that hospitality one day.

  2. Pete Murphy says:

    Thanks for stopping by, Julie, and for sharing your experience on Palmerston with my readers. It must have been wonderful to experience life boiled down to its basics in such an isolated place. It would be interesting to hear the perspective of a Palmerston resident who may have visited the U.S., and their opinion of life here vs. their tranquil setting.

  3. Brishen Hoff says:


    Here I have a formula for calculating the optimum population for any country.


    I have determined that the optimum population for Canada is 12,313 and for the USA it is 114,925:

    Brishen Hoff

  4. Pete Murphy says:

    Interesting, Brishen. Your calculation assumed that the human population prior to the advent of agriculture, about 5 million people several thousand years ago, is the maximum sustainable human population. That strikes me as awfully low for a couple of reasons:
    1. The human population from the time of Christ to about 1500 held fairly steady at about 250 million people.
    2. Your estimate for the U.S. is far lower than the native American population that existed before the arrival of the white man.
    3. Why should the sustainable population of humans be any less than that of other large mammals? For example, at the time that the white man first invaded North America, it is estimated that the bison population was about 55 million animals.

    I admit that I really have no idea what the “optimum” population would be, but feel certain it’s something quite less than we have today. When I speak of an “optimum population density,” I’m looking at it from an employment/standard of living perspective. It’s the point at which over-crowding begins to drive down per capita consumption, thus increasing unemployment and poverty. However, it’s very possible that this density would still be unsustainable in terms of its long term impact on resources and the environment.

    I think it would be a fantastic exercise for the world’s scientists and economists to collaborate on developing such a calculation, one that factored in every conceivable variable, including all economic and environmental constraints. Lacking that, I have an approach that’s much simpler. Since most scientists are now in agreement that the world is overpopulated, let’s set a goal of reducing the population by half, measure the results and decide what the next move should be.

  5. kiky says:

    pls is there an optimum population in any part of the world and if ther is can u give me adequate reasons for this?

    • Pete Murphy says:

      Consider Australia, with a population density of about 7 people per square mile. They are entirely self-sufficient in terms of resources and, just as importantly, they are not so crowded that per capita consumption has been eroded. As a result, they have no unemployment problem and have escaped the global financial crisis unscathed.

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