Idaho's flag is a state seal on a blue field, which puts it in the largest and least loved family of American state flags. Two things set it apart. The design is a direct copy of an infantry regiment's battle flag from the Philippines, which is why the official specifications still read like an order for military colors, down to the gilt fringe. And the seal at its center is the only US state seal designed by a woman, who used it to make a quiet argument for suffrage five years before Idaho granted it.
A battle flag from the Philippines
When the Spanish-American War began in 1898, Idaho had been a state for less than a decade. The First Idaho Infantry, its volunteer regiment, shipped out to the Philippines and fought around Manila in 1899 in the opening phase of the Philippine-American War. The regiment carried a blue silk battle flag bearing a rendering of the Idaho seal with the unit's name below it.
The soldiers came home to a state that had no flag of its own, and the legislature solved the problem by adopting theirs. The act of March 12, 1907 specified a silk flag with a blue field, five feet six inches on the fly, bordered with gilt fringe two and a half inches wide, with the state seal in the center. The regiment's name was swapped for the words "State of Idaho" on a red band edged in gold. A 1927 amendment tidied the specifications, but the flag remained what it began as: a regimental color pressed into civilian service. Its official 26:33 proportions, unlike any other state's, are a fossil of those origins.
Emma Edwards Green's seal
The seal has the better story. When Idaho's first state legislature convened in 1891, it announced a competition for a great seal, open to artists nationwide, with a $100 prize. Emma Edwards, a young art teacher who had recently arrived in Boise (and the daughter of a former Missouri governor), entered and won unanimously. Governor Norman B. Willey approved her $100 prize on May 5, 1891, and her design became the Great Seal of the State of Idaho. She married soon after, and as Emma Edwards Green she remains the only woman to have designed the great seal of an American state.
Her design choices were pointed. At the center she placed two figures: a miner with pick and shovel, for the industry that built the territory, and opposite him a woman holding scales of justice, with a liberty cap on a spear. Green drew them the same height. Women's suffrage, she later wrote, was "being agitated somewhat," and the leading men of the new state agreed it would eventually pass, so she gave the woman equal standing on the seal. Idaho's voters amended the constitution to enfranchise women in 1896, making it the fourth state where women could vote. The seal had gotten there first.
Reading the seal
Around the two figures, Green packed in most of Idaho's economy and scenery. The shield between them shows the Snake River winding through forested mountains, with a farmer plowing in the foreground. Above the shield is an elk's head, for the state's wildlife. Below are a sheaf of grain and two cornucopias, for agriculture's abundance. Sprigs of syringa, the state flower, appear in the design, and the whole is ringed by "Great Seal of the State of Idaho" with a scroll carrying the motto "Esto Perpetua": let it be perpetual. The phrase is traditionally attributed to the dying words of Paolo Sarpi, the seventeenth-century Venetian theologian, about his republic.
In 1957 the state had the seal professionally redrawn by Paul B. Evans, working with Caxton Printers of Caldwell, to standardize the artwork that engravers and flag makers had been improvising for decades. Evans kept Green's composition and figures while cleaning up the drawing, and it is his rendering that appears on flags made since.
Reputation and persistence
By the design standards vexillologists apply, Idaho's flag fails on schedule: a complex seal, illegible at distance, on the same blue field as twenty other states, with its name written on it twice (once in the seal's ring, once on the band below). The North American Vexillological Association's 2001 survey ranked it 64th of 72 flags. Periodic newspaper columns and design blogs have proposed replacements, often built on the syringa or the outline of the Sawtooths.
None has gone anywhere, and the reason is mostly the seal itself. A flag that carries the only woman-designed state seal in the country, drawn as a deliberate nod to suffrage in a state that delivered it early, is hard to argue off the pole on aesthetic grounds. The flag flies at the capitol in Boise, where the original painting of Green's seal design is preserved, and the 26:33 silk-and-fringe specification remains on the books, still describing, in effect, the battle flag of a regiment that mustered out in 1899.
References
[1] Idaho Secretary of State, "History of the Idaho State Seal" (including Emma Edwards Green's own account). https://sos.idaho.gov/elect/bluebook/Histseal.htm
[2] Idaho Code § 46-801 (state flag) and § 59-1005 (great seal).
[3] "Flag and seal of Idaho," Wikipedia. https://en.wikipedia.org/wiki/Flag_and_seal_of_Idaho
[4] "Emma Edwards Green," Wikipedia. https://en.wikipedia.org/wiki/Emma_Edwards_Green
[5] "Idaho: The only state with a seal designed by a woman. Meet Emma Edwards Greene," BoiseDev (2021). https://boisedev.com/news/2021/07/25/idaho-emma-edwards-greene/
[6] North American Vexillological Association, "2001 State and Provincial Flag Survey." https://nava.org/digital-library/design/surveys/
[7] US Flag Supply, "The History of the Idaho State Flag" (on the First Idaho Infantry battle flag). https://www.usflagsupply.com/u.s.-state-flag-history/idahos-flag-history.html