The “cowboy” is famous, but there is also the “cowgirl” (or “cow girl”). The name “cowgirl” appears in print in the 1880s.
 
Fort Worth has a National Cowgirl Museum and Hall of Fame.
   
   
National Cowgirl Museum and Hall of Fame
The National Cowgirl Museum and Hall of Fame is the only museum in the world dedicated to honoring and documenting the lives of legendary women who have distinguished themselves while exemplifying the pioneer spirit of the American West. It is the legacy of legends.
 
The purpose of the Hall of Fame is to preserve the history and impact of western women living roughly from the mid-1800s to the present—the pioneers, the artists and writers, the tribal leaders, the entertainers, the social activists, and the modern ranchers and rodeo cowgirls. Today, there are 176 amazing women who have been inducted into the National Cowgirl Hall of Fame since 1975.   
 
(Oxford English Dictionary)
cow-girl, a girl who tends cows; in U.S. fem. of COW-BOY
1884 E. BARKER Through Auvergne 119 We passed a group of *cow-girls singing. 1884 Boston (Mass.) Jrnl. 28 Nov. 2/3 A beautiful cowgirl lives near Murkel, Taylor county, Neb. She owns some stock, which she personally looks after.
 
22 November 1882, New York Times, pg. 7:
A remarkable etching in the present volume is Edmond Yon’s copy of Julien Dupre’s “Au Paturage.” A lusty peasant girl, her head done up in a part-colored handkerchief, her feet encased in heavy sabots, is holding on to a rope with all her might and main. The rope is attached to a halter, the motive power being imparted by an exceedingly ugly cow. Such a badly bred cow as it is never was seen before. Still, it is a French cow. This useful but headstrong animal sees her sisters in the pasture, and, quite indifferent to the cow-girl, is bent on chewing the cud in bovine company, so you may be quite certain, from the go and the stride of the cow, that the vachere, stands not the least chance of arresting her progress.
   
6 November 1883, Nevada State Journal (Reno, NV), pg. 2, col. 1:
If she had not been captured, this young lady might have become the wild cowgirl of the Texas prairie, and afforded material for scores of dime novels.
 
16 December 1884, Reno (NV) Evening Gazette, pg. 3, col. 4:
A Nebraska Cowgirl.
A beautiful cowgirl lives near Muriel, Taylor County, Nebraska. She owns some stock, which she personally looks after. At a recent round-up her dazzling beauty and graceful horsemanship were wonderful to behold. A yearling broke from the herd, which three cowboys failed to confine, when the beautiful girl dashed out after it, roping on the second circle, and pulled it by the horn of the saddle into the herd. The boys shouted, wept and have never ceased to love.