Cornrows are a traditional style of hair grooming of African origin where the hair is tightly braided very close to the scalp, using an underhand, upward motion to produce a continuous, raised row. This technique is somewhat similar to that used to produce a French braid, which is braided using an overhand, or inward, motion, resulting in a flat braid. Cornrows can be formed, as the name implies, in simple, straight lines; or, in complicated geometric or curvilinear designs. Often favored for their easy maintenance, cornrows can be left in for weeks at a time simply by carefully washing the hair using a stocking cap or hair net and then regularly oiling the scalp and hair. Cornrowed hairstyles are often adorned with beads or cowrie shells, in the African tradition. Depending on the region of the world, cornrows can be worn by either men or women.
A common way of styling hair in populations from sub-Saharan Africa, as well as North Africa, dynastic Egypt and the Horn, cornrows survived for centuries in the United States as a style of hair preparation among African slaves and their progeny. In 1963, when most African American women were loath to be seen in public with unstraightened hair, actor Cicely Tyson drew immediate notice when she sported cornrows on the popular network television series "East Side/West Side." The style gained wide popularity in the United States in the late 1960s and 1970s as part of the Black Pride Movement, when the trend was to reject straightening one's hair in favor of naptural hairstyles. Afros, strands of hair twisted into tight coils or wound with twine, and the wearing of geles (colorful, often elaborately wrapped head cloths) became other commonplace, African styles adopted by African American women.
In the wake of the Black Pride Movement, hundreds of beauty shops and salons sprang up across the United States delivering services exclusively, or as part of a range of options, to blacks who prefer natural (unstraightened) hairstyles. Many salons specialize in hair wrapping and braiding techniques, executing styles which can be exceedingly time-consuming and expensive. A single, braided style can take seven hours or more to complete, sometimes necessitating two or more salon visits. The tradeoff in the cost in time and money expended is that a well-executed, braided style can last a month or more without restyling, if properly groomed and cared for—and if executed on the naturally coarse, tightly coiled hair typically possessed by people of indigenous African descent. Such hair holds cornrows better, especially over time and, compared to the hair of other ethnic groups, generally has more tensile strength and tends to be less oily, which means it requires less frequent washing.
Cornrows also enjoyed some popularity among Caucasians after blonde actor Bo Derek wore beaded cornrows in the popular Blake Edwards movie 10, and became widely popular once again with the spread of hip-hop culture in the 1990s.
Cornrows are used by people of African ancestery in many different regions of the world. However, some controversy over their use has emerged in Nigeria, where hair braiding among men is considered a sign of femininity or homosexuality. 
Over the years, cornrows (along with dreadlocks) have been the subject of several disputes in the American workplace. Some employers have deemed them unsuitable for the office and have banned them - especially at-will firings and/or termination. African American employees and civil rights groups have countered that such attitudes evidence racial and cultural bias. Cornrows are perfectly appropriate in professional settings, they contend, citing their acceptability in venues such as the United Nations. Some such disputes have resulted in litigation.