Okay, this is a fun niche—there aren’t mountains of old-school Western romances where the heroine literally wears chaps and ropes steers, but there are some gorgeous historical books where women ride, wrangle, run ranches, and live like cowboys more often than like Victorian damsels.
If you want a classic, start with 'Riders of the Purple Sage' by Zane Grey — Jane Withersteen isn’t a bronc-busting cowgirl in the modern sense, but she’s a landowner and a fiercely capable frontier woman who drives much of the plot. For something more literary and female-fronted, check out 'The Girl of the Golden West' (the Belasco play and later Puccini opera) where Minnie is a tough, independent saloonwoman/frontier heroine. For modern historical fiction with real cowgirl work, I can’t praise 'The Hearts of Horses' by Molly Gloss enough — it’s set in the 1930s and follows a woman who becomes a wrangler; it reads like a love letter to horses and the lonely life on the range.
If you want grit, 'The Homesman' by Glendon Swarthout gives you Mary Bee Cuddy, a relentless frontier woman handling the brutal realities of settlement life. Also, authors who write historical western romance such as Linda Lael Miller often give their female leads ranches, guns, and agency, even if they’re framed in romance tropes. If you’re hunting specifically for heroines who behave like cowboys, search for terms like “cowgirl,” “wrangler heroine,” or “female rancher” in historical Western fiction — you’ll find gems tucked into literary and genre novels alike.