Constitution Day and September’s Patriotic Flag Days in Colorado

September is one of the most patriotic months on the calendar. Within a single stretch of days, four milestones arrive. The signing of the Constitution. The admission of a state. The birthday of a military branch. And a day of honor for those who never came home. Each one is a chance to fly the flag with purpose. They pass without the fanfare of the Fourth of July, but they carry the same weight. For many families, a quiet flag on the porch is exactly the right way to mark them.

This guide covers Constitution Day flags and the other patriotic anniversaries that fall in September. You’ll see what each day marks, how to fly the flag for it, and where to find American, historical, state, and military flags in Colorado. Flag World Company has served Aurora and the Front Range since 1989, and we’re glad to help you display them right.

September’s Patriotic Anniversaries at a Glance

Four anniversaries fall within ten days of each other this month. Each has its own flag and its own way of being marked:

• California Statehood Day — September 9, marking California’s admission as the 31st state in 1850.
• Constitution Day and Citizenship Day — September 17, the day the Constitution was signed in 1787.
• U.S. Air Force Birthday — September 18, when the Air Force became its own branch in 1947.
• National POW/MIA Recognition Day — September 18 in 2026, always the third Friday of the month.

That’s a lot of history in a short window. Here’s how to mark each one.

Constitution Day, September 17

Constitution Day is the anchor of the month. On September 17, 1787, delegates to the Constitutional Convention in Philadelphia signed the United States Constitution. Thirty-nine men signed the document that day. George Washington presided over the convention, and James Madison is remembered as the “Father of the Constitution.”

Congress designated September 17 as Constitution Day in 1952. Today it is also called Citizenship Day. It opens Constitution Week, which runs September 17 to 23. Each year the President may call on Americans to display the flag and observe the day. Schools across the country hold programs on the Constitution.

The Constitution set up the framework the country still runs on. It created three branches of government and a system of checks and balances between them. A few years later, the Bill of Rights added the first ten amendments and the freedoms Americans rely on today. Constitution Day is a chance to remember all of it. Constitution Day flags go up on porches, storefronts, and public buildings across the country to mark the occasion.

Flying Constitution Day Flags

The American flag is the natural centerpiece of the day. Flying it outside your home or business is a simple way to honor the document that shaped the country. Businesses along the Front Range often raise a fresh flag for the week, and a crisp flag out front sets a respectful tone for customers and staff alike. Many people choose to display it from September 17 through the end of Constitution Week. You can find outdoor and indoor options in our American flags collection.

Some people mark the day with a piece of the founding era. Historical flags like the 13-star flag and the Gadsden flag connect the moment to the nation’s beginnings. Our US historical flags collection carries those early designs. If you’d like to read the story behind them, our First 13 States and history of the American flag guides are a good place to start. Because the day opens a full week, many people leave the flag up through September 23. It’s a small way to keep the founding in view for more than a single day.

How Communities Mark the Week

Constitution Week brings small traditions worth knowing. Many towns hold a bell ringing at 4 p.m. Eastern on September 17, the hour the Constitution was signed. Schools, libraries, and civic groups host readings and programs. Some raise a flag to open the week. A flag on your own home fits right into that spirit, whether you fly it for the day or the full week.

California Statehood Day, September 9

September opens with a statehood anniversary. California entered the Union as the 31st state on September 9, 1850. Every state marks its own admission, and the state flag is how that history flies today.

Here in Colorado, that hits close to home. Our own state flag is one of the most recognizable in the country. A state flag is more than decoration. It’s a piece of local identity, flown at schools, city buildings, and homes across the state. September is a fitting time to fly it alongside the American flag. You can browse our state flags collection for all fifty states, or see our Colorado state flags page for the local favorite.

Honoring Service in September

Two of the month’s anniversaries honor those who serve. They land on the same date in 2026, September 18, and both are marked by flying a flag. One celebrates a branch of the military. The other remembers those who never made it home.

U.S. Air Force Birthday, September 18

The U.S. Air Force became its own branch of the military on September 18, 1947, under the National Security Act. Families and veterans mark the day by flying the Air Force flag, often beside the American flag. You’ll find branch flags in our armed forces flags collection, including a six-branch flag that honors every service at once. For an Air Force family, flying the branch flag on September 18 is a point of pride. Pairing it with the American flag makes a fitting display. The same goes for the other branches — many families fly the flag of the service their loved one wore.

National POW/MIA Recognition Day, September 18

National POW/MIA Recognition Day falls on the third Friday of September, which is September 18 in 2026. It honors service members held as prisoners of war and those still missing in action. The black-and-white POW/MIA flag carries the promise “You Are Not Forgotten.” On this day it flies at the U.S. Capitol, at government buildings, and at homes and businesses across the country.

The flag’s design is unmistakable. A stark image of a prisoner, a watchtower, and a strand of barbed wire sits above that famous line. It was created to keep the missing in the nation’s memory, and Congress has recognized it in law. On Recognition Day, it flies as a quiet reminder that the country has not stopped waiting.

Flying the POW/MIA flag is a simple, powerful way to observe the day. We carry it in our service and remembrance flags collection, alongside other flags of honor.

Pins, Patches, and Keepsakes

Not every tribute is a full flag. A lapel pin, a patch, or a keepsake carries the same respect in a smaller form. For the Air Force birthday or POW/MIA Recognition Day, a branch pin or a service patch is an easy way to show you remember. Browse our armed forces pins and military patches for something small to carry or give. For a veteran in your life, a pin from their branch makes a simple, meaningful gift. It’s a way to say their service is remembered.

Displaying Your Flags with Respect

September often means flying more than one flag at once. The American flag alongside a state flag, or beside a military branch flag. There’s a right way to arrange them, and it’s simple to follow. Getting it right is part of the respect the day is about.

• The American flag leads — it holds the position of honor. On adjacent poles, it sits on its own right, which is the viewer’s left.
• Never above another on the same pole — when the U.S. flag shares a pole with a state or other flag, it goes at the top.
• Raise it first, lower it last — the American flag is the first one up and the last one down.
• Light it after dark — a flag flown at night should be properly illuminated.

These simple rules keep any display looking sharp and respectful. For the full set, our U.S. Flag Code overview and flag etiquette guide walk through every detail.

Why These Days Are Worth Flying For

Taken together, September’s anniversaries tell a small story of the country. The founding, in Constitution Day. The growth of the nation, in a statehood anniversary. The people who defend it, in the Air Force birthday and POW/MIA Recognition Day. Flying a flag for any of them is a way to take part in that story. It doesn’t take a parade or a ceremony. A single flag, raised with intention, is enough. That’s the quiet tradition behind every one of these days.

Choosing Flags Built for Colorado

A flag flown for these days deserves to look its best, and Colorado’s weather is demanding. Strong sun at altitude, quick storms, and steady wind all wear on a flag over time. The right one, chosen well, holds its color far longer.

• Nylon flags — lightweight and quick to fly in a breeze, a great everyday choice for Colorado.
• Polyester flags — heavier and more durable, better for high-wind spots along the foothills.
• Indoor and parade flags — stick flags and mounted sets suit ceremonies, classrooms, and desks.

Our flags are American-made, and our Aurora team is glad to match you with the right size and material. If you’re not sure what fits your pole, you can contact us anytime. Free shipping is available on orders over $129.90 (restrictions apply).

Caring for Your Flag

A little care keeps a flag sharp through the season. Bring it in during heavy storms and high winds when you can. Let it dry fully before storing it. A gentle wash now and then keeps the colors bright. Treated well, a quality flag lasts season after season.

For Schools, Offices, and Organizations

Constitution Day brings programs in schools, and September’s service days matter to many workplaces and civic groups. A set of flags makes any observance more meaningful. Schools that receive federal funds are required to teach the Constitution on September 17, so a classroom set of flags often fits right into the lesson. Whether you need classroom stick flags, a lobby display, or a custom event banner, you can request a quote. Our team will help with sizing and quantities.

Building a September Display

If you want to mark the whole month, a small set of flags covers every anniversary in it. An American flag anchors the display and carries Constitution Day. Add your Colorado or home state flag for the 9th. Add a branch flag or the POW/MIA flag for the 18th. Stick flags and table sets work for a classroom, a desk, or a mantel. Full outdoor flags suit a pole or a storefront. You can mix sizes to fit the space you have. A single flag works just as well as a full set. If you’d like a hand choosing, our Aurora team is glad to help you build a display that fits the month and your budget.

Visit Our Aurora Showroom

Flag World Company — 1270 South Abilene St, Aurora, CO 80012. Call us at 303-623-0589. Our showroom is open Monday through Friday, 9:00 AM to 6:00 PM. Saturday hours are 10:00 AM to 6:00 PM, and Sunday hours are 11:00 AM to 4:00 PM. For directions and any holiday hours, see our hours and location page.

Frequently Asked Questions

What is Constitution Day, and why do we fly the flag?

Constitution Day marks September 17, 1787, the day the United States Constitution was signed in Philadelphia. Congress designated it in 1952. Each year the President may call on Americans to display the flag and observe the day, and it opens Constitution Week, September 17 to 23.

What patriotic holidays are in September?

September includes California Statehood Day on the 9th, Constitution Day on the 17th, the U.S. Air Force birthday on the 18th, and National POW/MIA Recognition Day, which falls on the third Friday, September 18 in 2026. Each is marked by flying a flag.

When is National POW/MIA Recognition Day in 2026?

It falls on Friday, September 18, 2026. The day always lands on the third Friday of September. Many people fly the black-and-white POW/MIA flag to honor prisoners of war and those still missing in action.

How do I display the American flag with a state or military flag?

The American flag holds the position of honor. On separate poles of the same height, it sits on its own right, which is the viewer’s left. On a shared pole, it goes at the top. It should be raised first and lowered last.

What flags fly on the U.S. Air Force birthday?

Many people fly the U.S. Air Force flag on September 18, often beside the American flag. A six-branch armed forces flag is a popular choice too, since it honors every service at once. Branch pins and patches are a smaller way to mark the day.

Can I fly a state flag and the American flag together?

Yes. Fly them from separate poles of the same height, with the American flag on its own right, which is the viewer’s left. On a single pole, the American flag goes at the top. The flags should be about the same size.

Where can I buy American and historical flags near Aurora, Colorado?

Flag World Company carries American, historical, state, and military flags in many sizes. You can browse them online or visit our Aurora showroom at 1270 South Abilene St to see the options in person.

Fly Them with Pride

September’s anniversaries are easy to overlook, but each one is worth honoring. A flag raised for Constitution Day, a state flag on the 9th, an Air Force or POW/MIA flag on the 18th. Small gestures that carry real meaning. You don’t have to observe all four. Even one, marked with a flag, keeps the meaning alive. However you mark the month across Colorado, Flag World Company is here to help you fly the right flag the right way.