Missouri's flag reads like a French tricolor turned on its side, which is no accident. Three horizontal stripes of red, white, and blue recall the flags of France and the United States at once, a fit for a state that began as a French colonial outpost and entered the Union through the Louisiana Purchase. At the center, ringed by 24 stars on a blue band, sits one of the busiest and most literal coats of arms in American state heraldry: bears, moon, eagle, helmet, and a Latin motto about the welfare of the people.
Mrs. Oliver's flag
In 1908, the Daughters of the American Revolution asked Marie Elizabeth Watkins Oliver of Cape Girardeau to chair a committee on a question that had somehow gone unanswered for 87 years: what was Missouri's flag? There wasn't one. Oliver wrote to every state that had adopted a flag, studied the replies, and concluded that Missouri's should carry its own coat of arms rather than a generic seal-on-blue arrangement. She sketched the tricolor, and the artwork for the arms was painted onto the design at her direction.
A bill to adopt the Oliver flag went to the legislature in 1909 and died. A rival proposal circulated in those years, built around the U.S. flag rather than state arms, and the two camps fought to a standstill. A second Oliver bill failed in 1911, the same year the State Capitol in Jefferson City burned, taking her original hand-painted flag with it. Oliver had a new version made in silk, sewn with the help of Mrs. S. D. MacFarland. The third attempt passed, and Governor Elliot Woolfolk Major signed the flag into law on March 22, 1913.
The silk flag survived, was restored, and is displayed at the James C. Kirkpatrick State Information Center in Jefferson City. Oliver is remembered in the state as "the Betsy Ross of Missouri," a title that undersells her: she researched, designed, and lobbied the thing through three sessions of the legislature.
Reading the arms
The coat of arms at the flag's center dates to 1822, the year after statehood. Its shield is split down the middle. The right half carries the arms of the United States, the bald eagle with olive branch and arrows. The left half is Missouri's own: a grizzly bear walking, above a crescent moon on blue. The crescent is heraldic shorthand for a second son, applied here because Missouri was the second state formed from the Louisiana Purchase, after Louisiana. Around the shield runs a belt buckled with the words "United We Stand Divided We Fall."
Two more grizzly bears hold the shield upright. Grizzlies still roamed Missouri in the 1820s, and the designers wanted an animal that read as strength and courage rather than borrowed European heraldry. The bears stand on a scroll bearing the state motto, "Salus Populi Suprema Lex Esto," a line from Cicero: let the welfare of the people be the supreme law. Below that is the Roman numeral MDCCCXX, 1820, the year of the Missouri Compromise that cleared the state's path to admission.
Above the shield sits a knight's helmet for state sovereignty, and above that a cloud of stars: one large star rising among 23 smaller ones, the 24th state joining the 23 already in the Union. The blue band around the whole arrangement repeats the arithmetic with 24 stars of equal size.
What the stripes mean
Oliver assigned the colors meanings in the plain civic vocabulary of her era: red for valor, white for purity, blue for permanency, vigilance, and justice. But the tricolor also does historical work. Red, white, and blue are the colors of both France, which founded St. Louis and Ste. Genevieve, and the United States, which bought the territory in 1803. A Missourian in 1913 could read either flag into the stripes, and Oliver seems to have intended both readings.
The white center stripe gives the arms a clean field, which makes Missouri's flag slightly more legible than the standard seal-on-blue design, though only slightly. At flagpole distance the arms blur into a roundel, and the tricolor risks being mistaken for the flags of the Netherlands, Luxembourg, or Paraguay. In the North American Vexillological Association's 2001 survey of state and provincial flags, Missouri finished in the lower half of the table, dragged down by the detailed centerpiece.
An unchanged design
Missouri has flown the same flag since 1913 with no revisions, no added lettering, and no serious redesign movement, which makes it an outlier among seal-and-arms states. Periodic newspaper columns propose simplifications, but no bill has come close. The flag flies over the Capitol in Jefferson City, whose current building, completed in 1917, replaced the one whose fire nearly took the flag's original with it.
The bears, at least, have outlasted their models. Grizzlies were gone from Missouri within a few decades of the arms' design; the state's living bears are black bears, whose population has been recovering since the 1990s. The flag keeps the grizzlies anyway, at full heraldic size.
References
[1] Missouri Secretary of State, "The Missouri State Flag." https://www.sos.mo.gov/CMSImages/Publications/StateFlag.pdf
[2] State Historical Society of Missouri, "Marie Watkins Oliver," Historic Missourians. https://historicmissourians.shsmo.org/marie-watkins-oliver/
[3] Wikipedia, "Flag of Missouri." https://en.wikipedia.org/wiki/Flag_of_Missouri
[4] Britannica, "Flag of Missouri." https://www.britannica.com/topic/flag-of-Missouri
[5] Missouri Secretary of State, "State Symbols of Missouri." https://www.sos.mo.gov/CMSImages/Publications/StateSymbols.pdf