On May 20, 1873, the U.S. Patent Office granted patent #139,121 to Levi Strauss & Co. and a tailor named Jacob Davis. It covered rivets on denim work pants, added for strength, and Levi's calls that the first official blue jean. Nobody in that room was thinking about a sundress with a square neck. I still like knowing that denim dresses start from a piece of hardware on a pocket corner.

 

The cloth itself is older and more European than the story suggests. Levi's own denim dictionary traces the word to Nimes, France, where a serge twill was made in the 1850s, and says that early fabric was not the cotton denim we know today. All-cotton denim came later, first in England and then perfected in American mills. So a dress in dark indigo carries a French town, an English loom and a San Francisco patent, which is a lot of history for something you throw on to get to the market. I went deeper on a related idea in Barn Jacket Outfits: Canvas and Waxed Layers With Dark Denim.

 

October is the right month to shop the midis. Take the Esme from DL1961, a sleeveless fitted sheath with vertical seaming: with a fine-gauge turtleneck underneath and tights, it reads as a proper fall dress. The Square Neck from Odd Muse, in dark indigo with a full skirt, is the one I would pair with a short cropped cardigan and ankle boots. The Maggy London drop waist has side pockets and a gathered skirt, so it moves like a skirt and suits long walks. And the Delancy from French Connection, a mid-blue fit and flare, is the easy one to belt.

 

A test before you commit: sit down in it and raise both arms. Midi denim has no give in a woven body, so check the armholes and the seat, and make sure the hem clears your boot shaft by a few inches.

Short denim only works in fall if you plan the layers, so think of the mini as a base rather than a finished outfit. The Highland from BDG, ruched at the cap sleeve with a square neck, is a good fit over a thin long-sleeve tee. Tights and knee boots finish it. That is the whole formula, and it is hard to get wrong. If you want to keep going, Clean Unclean: Lived-In Denim, Undone Layers and Easy Tops is the one I would read next.

 

The Good American V-neck minidress buttons down the front, which means you can leave the last few buttons open over a patterned skirt layer or close them for a cleaner line. The Holly from Cinq à Sept has puff sleeves, a front zip and a tie belt, so it already has some shape. The Mila from Alice + Olivia is lighter in color with a twist front and a tiered skirt, and I would put a dark brown suede boot with it to cool down all that pale blue. The Steve Madden Dyanne has a pleated skirt and a front zip, which makes it a good fit for a desk with a blazer on top.

 

Fitting-room test: sit, then bend to pick up a bag. A mini that rides up when you sit is a mini you will tug at all day. Look at the hem and the zip too, because a dress that looks sharp standing can gape when you move.

 

What I would skip: the very light washes with sheer tights in cold weather. Pale denim looks washed out against black legs, and dark indigo does better once the temperature drops.

Denim started life as hard-wearing cloth, and a maxi lets it stay that way: it is already a coat of sorts from the waist down. The Donna from Donna Karan New York is a sleeveless dark denim maxi with a V-neck, an empire seam and side pockets, and I would wear it with a fitted knit underneath so the shoulders get some warmth. The Callum from Petal & Pup, in dark indigo with a flared skirt and pockets, is the practical one for a long day on your feet.

 

For something with more going on, the APNY tiered maxi has short puff sleeves and a flowy skirt, so I would put a slim cardigan over it and keep the shoes flat. The Daisy Street dress is a washed green-blue with an open tie back and puff sleeves, and it needs a long-sleeve top underneath if the day is chilly. Avec Les Filles made a cargo version with a zip front and a front slit, which is the choice for anyone who wants a maxi that still reads a little tough, with a leather boot and a short jacket.

 

Check the hem length with the shoes you actually plan to wear. A maxi that grazes the floor in flats will drag in a boot with a heel, and a denim hem picks up rain and city grime fast. Hold the fabric against your hand too: a heavy dark twill should feel substantial, not papery.

 

What I would skip: a long denim skirt with a long coat in a matching blue. Pick a coat in camel or olive and let the dress be the one blue thing.

A shirt dress is the denim dress that has the longest working life, because it can be a jacket, a dress or a tunic on its own. The Foxcroft Agnes has three-quarter sleeves and a tie waist, so it works in early fall without anything underneath. The Polo Ralph Lauren one is a true chambray with roll sleeves and a flared skirt, which is the softer, lighter way to wear the idea. Frank & Eileen add patch pockets to a light denim shirtdress with a button front.

 

For dark blue, the Wash Lab Denim Allura is a long-sleeve midi with chest pockets and a tie belt. The Zoe and Claire version has short sleeves and a full midi skirt, and I would layer a thin knit over it with the sleeves pushed up. The Sade from Fifteen Twenty is belted with a button front, and the Karen Kane Western has a light chambray look with chest pockets and a tie belt, an easy partner for boots.

 

One trick from a buttoned dress: leave the last few buttons undone at the hem and let a skirt or slip show underneath, or fasten everything and wear it open over a knit dress as a light coat. Fitting test: button it to the top, then raise your arms and check the gap between the buttons across the bust. If it pulls, go up a size and let the belt do the shaping.

 

What I would skip: a belt wider than the dress can carry. On a lightweight chambray, a thick buckle just drags the waist into folds.

The pinafore is the most layer-friendly denim dress you can buy, because it was designed to sit over something else. The Bayeas pinafore in light denim has a scoop neck and a flared skirt, and in October I would put it over a striped long-sleeve tee or a fine knit with tights. The True Religion overall minidress, faded blue with bib pockets and adjustable straps, goes over a turtleneck a nod to the 1990s, when overalls turned up even on red carpets. EDIKTED makes two overall minis, one in mid blue with buckle straps and one in light blue, so pick the wash that suits your boots.

 

Black is a good option for fall: the Disturbia Ayr is a black denim pinafore with a V-neck, front pockets and a broderie hem, which sits well over a white shirt. The Line & Dot Monah has a pinstripe and a square neck, so it can do a smarter day look with a blazer. Then there are the strapless pieces. The Free People Alexa is seamed and strapless in mid blue, and the BDG Sweet Talker has a lace-up corset bodice with a tiered ruffle skirt. Both want a sweater or a cropped jacket over them in cooler weather.

 

Check the straps. Adjustable straps should hold their length when you reach up, and a bib that sits flat is better than one that gaps. For the strapless styles, lift your arms and walk around the fitting room before you decide.

 

What I would skip: the strapless and corset styles as a stand-alone outfit on a cold night. They are for layering, and a thin knit is what makes them work in fall.

I would start with the dress that fits my life: a shirt dress if I walk, a pinafore if I layer, a midi if I want to be dressed up. Then I would add the base layer, which is a turtleneck or long-sleeve tee, and tights in black or something close to your boot color. Last come the boots and one knit on top, a cardigan the length of the dress or one that hits at the waist.

 

People talk about double denim, the jeans and jacket look that got its Canadian tuxedo name after Levi's made Bing Crosby a denim tuxedo in 1951 when a Vancouver hotel turned him away in denim. The nickname came much later, around 2000, but the idea is old. A denim jacket over a denim dress can work if you vary the washes, and I would try it with an indigo dress and a pale jacket. That is what I would do on a Saturday in October.