Say I have a modern Era USA town. This town has a population of about 30,000 and an area of about 30 square miles (79.4 square km). It is a predominantly rural area, lots of farmland around the town.

Something happens in this town. A plague outbreak or a zombie outbreak or whatever. Something highly contagious by contact.

So you need to isolate the town. No one in, no one out. (people primarily. Cattle and horses too, though they are at lower risk. So far, they feel that wildlife like deer or etc are not a threat. Plants cannot carry the infection.

There is one major interstate just outside the city, and one minor parkway from that interstate through the middle of town. There are a couple of state highways through town as well as numerous rural streets.

How could we insure the town is contained? Is it even possible to "lay seige" to a modern location?

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    $\begingroup$ Another point to clarify is if you want the city supplied or if you don't care if people inside starve or lack important suplies. $\endgroup$
    – Pere
    Commented Aug 19, 2017 at 14:41
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    $\begingroup$ 30000 people in 30 square miles is a thousand people per square mile. That is more like the population density of New Jersey than rural Idaho! en.m.wikipedia.org/wiki/… $\endgroup$
    – bishop
    Commented Aug 19, 2017 at 17:33
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    $\begingroup$ Have the president build a wall and make the townsfolk pay for it. $\endgroup$
    – KalleMP
    Commented Aug 19, 2017 at 20:21
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    $\begingroup$ How long must the containment last, is it cheaper to accidentally nuke the place? (Andromeda strain film can give ideas) $\endgroup$
    – KalleMP
    Commented Aug 19, 2017 at 20:22
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    $\begingroup$ The Simpsons - The Movie ? $\endgroup$ Commented Aug 20, 2017 at 12:15

8 Answers 8


Yes it is possible. No, it is not going to be cheap. It was done with West Berlin until 1989.

  • Place heavily armed check points on all the road, with all the necessary to forcefully stop any vehicle trying to past them. If you have been to LAX airport car rental, you know what I mean

enter image description here

  • Set patrolling of the border where no roads are present. You can also mine the ground, set motion and infrared detectors with automatic machine guns for better control.
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    $\begingroup$ I'd just note that Berlin is an example of why it's hard. Plenty of people got under/over/around the Berlin Wall, which was fine in our case, but less fine if it's a plague carrier. $\endgroup$
    – ceejayoz
    Commented Aug 19, 2017 at 16:48
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    $\begingroup$ @ceejayoz: In a rural town, you have room to make wide dead zones between an inner and outer wall, so you can detect (and shoot?) people / animals that breach one level of containment. In Berlin, the no-mans-land was only 30 to 100 yd wide, and routing the wall to avoid hard-to-defend areas wasn't as easy because of political factors (IDK if this mattered). Also, the early versions of the Berlin wall were less imposing than the final version that came down in 1989. Also, there was significant traffic through the wall at checkpoints, which you don't have as much of in a quarantine situation. $\endgroup$ Commented Aug 19, 2017 at 20:16
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    $\begingroup$ For practical reasons it should be noted that the Berlin wall was already before its construction a (somewhat mutually agreed) border equipped with simpler fences and controls, thus allowing the very sudden closing $\endgroup$ Commented Aug 20, 2017 at 12:24
  • $\begingroup$ If this is for a short term, they don't need to build permanent tire poppers. Police have deployable ones they could lay down, or they could spread caltrops along the road. $\endgroup$ Commented Aug 21, 2017 at 1:26
  • $\begingroup$ @ceejayoz also, even the final version of the Berlin wall, which saw hardly any escapes, was based on 1970s technology. The GDR was actively developing a "Wall 2000" concept that would have made things pretty much airtight, and sunk so deep that tunnelling under it would be prohibitively difficult without specialised equipment. Just about the only thing missing were anti aircraft guns and missiles to prevent rescues by air (which did happen at least once). $\endgroup$
    – jwenting
    Commented Aug 21, 2017 at 8:16

If situation is bad enough to suspend civil rights and warrant enforcing quarantine with weapons, if necessary then military would take over and:

  • block highways to prevent unwanted exchange with external world.
  • draw a perimeter crossing as little building as possible.
  • rise a concertina wire fence at perimeter.
  • completely flatten out a ring around perimeter at least 100m wide.
  • set armed watchposts to control the perimeter.
  • build two more alarmed fences, one right inside the first concertina wire fence and the other on the outside border, inline with watch towers.
  • catch your breath.
  • depending on seriousness of infection flamethrowers could be deployed.
  • defensively patrol "no man zone".

Note that, in modern societies (e.g.: U.S.), such measures are unlikely to be decided and deployed before someone manages to escape quarantine, especially if the city is big and highways carry a lot of traffic.

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    $\begingroup$ Pointing out that probably you can't set up those kind of containment measures before someone escapes deserved a plus. $\endgroup$
    – Liquid
    Commented Aug 19, 2017 at 15:16

If you have unintelligent agents (zombies, animals) they have no reason to stick to roads but they are easier to stop. The roads might be tried by refugees in vehicles. It is so easy to make a road impassable (e.g. jersey barriers) that people in vehicles will go off-road also.

So how to rapidly encircle your area with a barrier?

enter image description here

source: https://www.youtube.com/watch?v=R-01-bbFzLM

It looks to me like this wire was laid down at about 1 mile/hour. On a vendor website I found they state it can be deployed at 20 meters/minute which is about the same. I estimate your quarantine area to have a circumference of 18 miles. You can figure out how long it would take to lay down an 18 mile circle of this stuff based on how many trucks you deploy. Not long.

It occurs to me that all concertina wire available has blades. Sentient things want to avoid being cut. Getting tangled in the wire happens also. If the blades were barbed it might sacrifice some cutting / injuring power but gain some tangling power which would be better against zombies.

Then you set out robot sentries. These paintball robot sentries are cheap and terrifying. You can find many videos posted by people who have built their own.


enter image description here

The area covered by a sentry depends on the range of its weapon and its sensor. One could have the sentry broadcast a message twice before it shoots to ward off intelligent refugees. You could set out many of these, with weapons appropriate for what you expect to try the wire.

The other reason for the robot sentries is that if one got triggered, it could turn on a camera and broadcast what it saw. So if you see your wire and sentries overwhelmed by a wave of zombies, or me in my fortified truck charging the wire, you could deploy an armed helicopter to the area.

I am thinking of a scene where the heroes are going to cross the fence. They have seen what happens to the infected who try it and seen what happens to me in my fortified truck. So they approach the wire very, very slowly, carrying large pieces of weighted plywood that they set across the wire very, very slowly.

  • $\begingroup$ that sentry gun would be more impressive if it were shown to actually hit something. Eg. it doesn't seem to be leading its shots. $\endgroup$
    – ths
    Commented Aug 21, 2017 at 10:31
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    $\begingroup$ @ths - you can while away the time on youtube looking at home brew sentry paintball guns. I will admit I picked the first video that illustrated the principle. $\endgroup$
    – Willk
    Commented Aug 22, 2017 at 11:13

The seal off must happen in steps if you want it as fast as possible.

First step: Block the roads.

This is obvious because this will be the main route where people want to try to get in and out. You need only 3 dozen heavily armed people with blockages, if necessary you can use cars/trucks.

Second step: Place snipers with thermal imaging, IR and nightsight around the city with helicopters and warn people to stay off with megaphone and leaflets.

I think 1-2 companies are sufficient. They are placed in strategic, elevated positions and if someone approaches, a shot before the feet will be convincing enough that the person retreats. If this is not enough or if it is an animal, the warning shots are switched to killing shots. Still if someone is desperate, he can try to escape by hiding behind the wheel of a cross-country vehicle and driving outside the road. Shots can destroy the motor, but sniper rifles are notoriously slow to reload, so with luck someone can escape. Another option is if inside is someone with military training in isolation (sniper, special-ops) who may be able to escape the encirclement.

Third step: Now the barricade will be constructed as hinted in the other answers. Everything will be locked down: roads, rivers, canalisation(!).

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    $\begingroup$ I like that this gives a phased approach over time. $\endgroup$
    – CaM
    Commented Aug 19, 2017 at 21:29
  • $\begingroup$ I like that this comment gives it's take on the answer. $\endgroup$
    – a20
    Commented Aug 21, 2017 at 4:41

I might not directly answer the question but it would be easier to have all the townspeople moved to a closed "facility" to cure them instead of letting the run around in an open area.

The promise of a cure should be enough for most of the to willingly accept being moved.

For the reluctant ones, you can just cut water and food supply, they will quickly change their mind.

  • $\begingroup$ This may be the only viable answer. A town full of people will need to be fed and watered so there will be some kind of crates going in and friends or family will smuggle stuff in that can fly out and spread the disease. Locked up in a FAMA quarantine camp would allow you to control the amount of resources the inmates have to hand much better. it would also be more concentrated (such camps are popular for exactly this reason) requiring much less perimeter per capita. .... $\endgroup$
    – KalleMP
    Commented Aug 24, 2017 at 20:18
  • $\begingroup$ .... Groups could be split and homogenised supplying leverage and efficiency of services. Male:female, old:young splits with hinted threat of reprisals if some one attempts escape. $\endgroup$
    – KalleMP
    Commented Aug 24, 2017 at 20:18

Domed City

Just put a giant dome over the entire town!

And before you put it of as pure fiction.

It has been proposed before.


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    $\begingroup$ So now it's both domed and doomed. $\endgroup$
    – pipe
    Commented Aug 21, 2017 at 12:35
  • $\begingroup$ Haha yeah. And it is so much better then the accepted answer too. Because you can just dig a tunnel or get a chopper to get you out of the city. With a dome you can deal with tunneler (to a certain point) and choppers much better without having to deal with constant costs of patrols. And you can regulate the conidtions of within the dome much better. Furthermore animals won't be a problem either. It's perfect! $\endgroup$ Commented Aug 21, 2017 at 13:05
  • $\begingroup$ I'm not sure how a dome prevents tunnelling, unless you're intending to continue it underground as well? Compared to the accepted answer this sounds like it would also take a lot longer to organise and construct. $\endgroup$ Commented Aug 21, 2017 at 13:22
  • $\begingroup$ Well you can't just place a dome and leave it there. You will need some kind of fundation. $\endgroup$ Commented Aug 21, 2017 at 13:40

First, put down barbed wire and machine gun nests. cut down everything higher then a shrub, for any distance you seem most dramatic, like lets say 666 meters. Place anti vehicle and anti personal mines. While doing that, build a wall and make it huge, with sentries. Remove inner guards to lessen the probability of incidents. Weld all gates shut.

Dont forget about that pesky sewers and planes!


Direct use of high fences and concertina wires, like Trump's border wall. This seems to be a very effective way, because Trump's border walls are getting longer and longer.


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