What Is a Garrison Flag, and How Does It Differ from a Storm Flag?
The garrison flag vs storm flag distinction is a size-and-duty question, not a stylistic one. A garrison flag is the largest standard U.S. flag in military use: 20 ft hoist by 38 ft fly, codified in Army Regulation 840-10. A storm flag is the smallest: 5 ft hoist by 9 ft 6 in fly, flown specifically in inclement weather to protect the larger, more costly flags from damage. Between them sits the post flag, the everyday workhorse.
What Are All the Official Military Flag Sizes?
AR 840-10 defines four distinct outdoor U.S. flag sizes for Army use. The Navy, Marine Corps, and Coast Guard follow slightly different dimensions for the post flag tier. Here is the complete hierarchy:
| Flag Name | Hoist | Fly | Approx. Area | When Flown |
|---|---|---|---|---|
| Garrison | 20 ft | 38 ft | 760 sq ft | Holidays & special occasions |
| Post (Army) | 8 ft 11⅜ in | 17 ft | ~152 sq ft | Every day (default) |
| Post (USMC/Navy/USCG) | 10 ft | 19 ft | 190 sq ft | Every day (default) |
| Field | 6 ft 8 in | 12 ft | 80 sq ft | Distinguished visitors only |
| Storm | 5 ft | 9 ft 6 in | 47.5 sq ft | Inclement weather |
| Internment/Burial | 5 ft | 9 ft 6 in | 47.5 sq ft | Funeral honors |
Notice that the storm flag and internment flag share the same dimensions. All of the above carry a 1:1.9 aspect ratio, matching Executive Order 10834's proportions for the U.S. flag. One notable outlier: the Air Force does not fly a garrison-size flag at all, using its own "base flag" terminology at the post-flag scale.
Which Flag Flies When? The Duty Rotation Explained
The three-tier rotation is simple once you see the logic: use the biggest flag you can safely fly, and step down when conditions prevent it.
- Post flag: the default. Flies every day a garrison or storm flag is not up.
- Garrison flag: replaces the post flag on federal holidays and special occasions designated by AR 840-10 or Presidential Proclamation. If no garrison flag is available, the post flag stands in.
- Storm flag: overrides everything in severe weather, protecting the larger, more expensive flags from wind and rain damage.
- Field flag: a special-purpose display flag raised only when distinguished visitors are present, alongside a positional field flag.
Handling scale matches the size. Per TC 3-21.5, the storm flag requires two handlers, the post flag needs six, and the garrison flag takes eight personnel to raise and lower properly.
The Fort McHenry Twist: Which Flag Actually Flew During the Battle?
Almost every retelling of the Star-Spangled Banner story implies a massive garrison flag waved defiantly through the rockets' red glare. The reality is the reverse. The storm flag flew throughout the entire 25-hour bombardment on the night of September 13–14, 1814, because heavy rain made flying the massive garrison flag impractical.
Only after the British ceased fire and began to retreat did Major Armistead order the storm flag lowered and the great garrison flag raised. That morning flag, measuring 30 by 42 ft and sewn in 1813 by Baltimore flagmaker Mary Pickersgill, required about 400 yards of fabric, weighed more than 50 pounds, and needed 11 men to hoist it to the top of its 90-foot pole. Francis Scott Key, watching from a British warship two miles away, saw that garrison flag catch the sunrise and wrote what became the national anthem.
The Great Garrison Flag, now preserved at the Smithsonian's National Museum of American History, is technically larger than today's standard 20x38 ft military spec. Major Armistead had wanted something the British would have "no difficulty in seeing from a distance." For context on other historically significant flag designs, see the Historical & Patriotic Flags collection or read about the 13-star flag variants and their America 250th significance.
Are the "Garrison Flags" on Amazon Real Garrison Flags?
No. A search for "garrison flag" on major marketplaces turns up 3x5, 4x6, and 5x8 ft flags labeled with the word "garrison." These are misnamed decorative flags. A true garrison flag is 20x38 ft and covers roughly 760 square feet. A 3x5 ft flag labeled "garrison" is off by a factor of about 50 in area. No federal specification recognizes those sizes as garrison flags; the term is being used as a marketing adjective rather than a technical classification. If you need an accurately described American flag in standard residential sizes, browse the full American Flags collection for size options that are honestly labeled.
Can a Homeowner Actually Buy and Fly a Garrison Flag?
There is no federal law barring a private citizen from owning or flying a 20x38 ft flag. The practical barriers make it unrealistic for nearly every home:
- Pole height: a 20x38 ft flag needs a flagpole of roughly 65 to 100 ft to clear the ground and look proportional. Standard residential poles top out at 20–25 ft; commercial-grade poles reach 35–40 ft.
- Installation requirements: poles above 25 ft typically require professional installation with engineered footings.
- Weight and hardware: the flag fabric alone can exceed 50 lbs when wet, requiring heavy-duty hardware rated for that load.
- HOA and zoning: local ordinances may restrict pole height even where the federal Flag Protection Act applies.
- Custom order only: no standard retail stock carries a certified 20x38 ft civilian flag; these are special-order items.
Non-standard commercial "garrison-style" sizes (18x34, 20x36, 22x38 ft) exist and are fine for private display, but they are not Government Specification (G-spec) compliant and would not pass a military or government inspection.
What Is the Largest Flag a Residential or Commercial Pole Can Realistically Fly?
Match flag size to pole height using the standard rule: the flag's fly (long dimension) should be no more than one-quarter to one-third of the pole height.
| Pole Height | Recommended Max Flag Size | Typical Setting |
|---|---|---|
| 20 ft | 3x5 ft | Residential house mount / yard |
| 25 ft | 4x6 ft | Residential / small commercial |
| 35 ft | 5x8 ft | Commercial / municipal |
| 40–50 ft | 6x10 ft | Large commercial / institutional |
| 60–80 ft | 10x15 to 10x19 ft | Large commercial / light industrial |
| 90–100 ft | 20x38 ft (garrison spec) | Military installation / major landmark |
For most homeowners making a strong patriotic statement, a 5x8 ft or 6x10 ft flag on a 35-40 ft commercial pole is the practical ceiling. The Nylon American Flag (100% Made in USA) and the Spun Poly American Flag (100% Made in USA) are both available in larger residential sizes and are built for all-weather outdoor use. For a complete ready-to-fly system, the Premium American Flag Display Set pairs a flag with pole, mount, and aluminum rings. Browse all flagpole options to match your installation height. Need help sizing a second flag on the same pole? The guide on what size second flag to fly covers proportions in detail.
If your interest is specifically in authentic military flag designations and branch insignia, the Military Flags collection covers those options.
Common Mistakes to Avoid
- Buying a "garrison flag" off a marketplace listing without checking dimensions. Verify the hoist and fly measurements. If they say 3x5 or 5x8 ft, it is a decorative flag, not a specification garrison flag.
- Assuming the Star-Spangled Banner flew through the bombardment. The storm flag flew through the battle; the garrison flag went up the next morning after the British withdrew.
- Trying to fly an oversized flag on an undersized pole. A flag too large for its pole wraps, tears at the header, and can stress the pole in wind. See the guide on how to keep a flag from wrapping around the pole for related pole-compatibility tips.
- Treating Army and other-branch post flag sizes as identical. The Army post flag is 8 ft 11⅜ in x 17 ft; the Marine Corps, Navy, and Coast Guard use 10x19 ft. Mixing up the numbers matters if you are sourcing a compliant flag for official use.
- Ignoring zoning before ordering a custom tall pole. Many municipalities cap residential flagpole height at 20–25 ft regardless of federal flag-protection statutes. Check local ordinances before purchasing a commercial-grade pole.
- Assuming the Air Force follows the same garrison-flag protocol as the Army. It does not. The Air Force flies no garrison-size flag.
Frequently Asked Questions
What is the official garrison flag size?
The official garrison flag size under Army Regulation 840-10 is 20 ft hoist by 38 ft fly, with a 1:1.9 aspect ratio. This is the same proportional ratio specified in Executive Order 10834 for all U.S. flags. The garrison flag is the largest standard outdoor U.S. flag in current military use.
What is a storm flag size?
A storm flag measures 5 ft hoist by 9 ft 6 in fly per AR 840-10. It shares those exact dimensions with the military internment/burial flag. The storm flag is flown in inclement weather to protect the larger and more expensive post and garrison flags from damage.
What is a post flag size?
The Army post flag is 8 ft 11⅜ in hoist by 17 ft fly. The Marine Corps, Navy, and Coast Guard use a larger version at 10 ft by 19 ft. The post flag is the default daily flag at a military installation, flying on all days when the garrison or storm flag is not in use.
Did the garrison flag fly at Fort McHenry during the bombardment?
No. The smaller storm flag flew throughout the 25-hour bombardment on the night of September 13–14, 1814, because heavy rain made flying the massive garrison flag impractical. Major Armistead ordered the storm flag lowered and the 30x42 ft garrison flag raised the morning of September 14 after the British withdrew, and that was the flag Francis Scott Key saw when he wrote the Star-Spangled Banner.
Can a homeowner buy and fly a garrison flag?
Yes, legally, but almost no residential property can accommodate one. A true 20x38 ft garrison flag requires a pole of roughly 65–100 ft, professional installation, hardware rated for 50+ lbs of wet fabric, and must clear local zoning restrictions on pole height. For most homes and businesses, the largest practical flag is 5x8 ft or 6x10 ft on a 35–40 ft pole.