Quoting from Wikipedia:

Windsor developed its gypsum deposits, usually selling it to American markets at Passamaquoddy Bay. Often this trade was illegal. In 1820 an effort to stop this smuggling trade resulted in the "Plaster War", in which local smugglers resoundingly defeated the efforts of New Brunswick officials to bring the trade under their control.

The source seem to be the 2006 book Borderland Smuggling by J. M. Smith1, for which the summary contains this part:

Joshua Smith examines the reasons for smuggling in this area and how three conflicts in early republic history—the 1809 Flour War, the War of 1812, and the 1820 Plaster War—reveal smuggling's relationship to crime, borderlands, and the transition from mercantilism to capitalism.

Why would this be illegal?

I assume that reading the whole book would enlighten me, but I don't have access to it, and for some reason it's also listed in the genre "True Crime" which makes me believe it may be a little more sensationalized than I'm comfortable with.

1. Smith, J. M. (2006). Borderland Smuggling: Patriots, Loyalists, and Illicit Trade in the Northeast, 1783-1820. United States: University Press of Florida.

  • 2
    Typical reason for export restrictions would be for military reasons (not likely for Canada?) or to keep the prices low for domestic consumers by restricting demand to the home country.
    – T.E.D.
    Commented Apr 30 at 20:48
  • 7
    It wasn't illegal when the tarfiff was paid. That's most often what "smuggling" means.
    – Brian Z
    Commented May 1 at 1:25
  • 4
    (Relatively) free trade is a 20th century post WW2 (and colonies) thing. Protectionism was the name of the game then.
    – Jon Custer
    Commented May 1 at 1:34

1 Answer 1


Entering your question into google results in the Plaster War

The problem persisted for years and in 1816-17, the New Brunswick and Nova Scotia colonial governments passed complementary laws that tried to prevent landing gypsum along known smuggling routes in the US or in the provinces. The goal was to have gypsum exports controlled by legitimate merchants and shipowners who would pay the duties. However, the Americans retaliated with a law of their own and the effort failed.

@MJ713 found a copy of the New Brunswick 1816 law

In 1820, the New Brunswick government, pushed by Saint John merchants, passed a new law that appointed a "preventative officer" with wide powers to control the gypsum trade. Stephen Humbert of Saint John was appointed to the role.


By various means, including kidnapping and armed resistance, in addition to the active participation of law enforcement officers, American flour entered British territory illegally and British gypsum, or plaster used as a fertilizer, flowed through American waters into U.S. fields as contraband. Thus, the U.S.-Canadian border meant very little to entrepreneurial men in both regions, and Smith concludes that interregional commerce tends "to diminish the importance of borders" (p. 16). Contraband Chronicles

  • 10
    So the answer seems to be "tax evasion"?
    – Yakk
    Commented May 1 at 14:13
  • 3
    Seems to me to be a law designed to inhibit tax evasion, which I had thought was already illegal. Perhaps it raises the penalty or perhaps it makes prosecution easier. or perhaps it is performative legislation. "look! we've done something" Even if what we have done is entirely symbolic. But I try to confine my cynicism to comments and not include it in my answers.
    – MCW
    Commented May 1 at 14:21
  • 3
    I found a copy of the New Brunswick 1816 law: bnald.lib.unb.ca/sites/default/files/…
    – MJ713
    Commented May 1 at 18:21
  • Your link returns a SQL error on the website.
    – Spencer
    Commented May 1 at 19:58
  • That link works fine for me.
    – MCW
    Commented May 1 at 20:53

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