The Oregon swallowtail (Papilio machaon oregonius, sometimes classified as Papilio oregonius or Papilio bairdii oregonius) is a subspecies of swallowtail butterfly native to the United States of America, Oregon, Washington, and Idaho and south-central British Columbia in Canada. In 1976, it became one of the first four butterflies that the United States Postal Service placed on a U.S. stamp.

The Oregon swallowtail was declared the state insect of Oregon in 1979 by the Legislative Assembly.

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