I can answer for California, though it was probably different in other jurisdictions.

In the 1960s in California the radical group the Black Panther Party carried firearms as a show of strength and to protect themselves against police. This was perfectly legal according to California's laws at the time. However, it made Republican governor Ronald Regan, and the republican controlled state congress nervous. In 1967 passed a law, called the Mulford Act, outlawing open carry, at the time one of the strictest gun control statues in the nation.

As more states passed laws against the open carry of arms in the late 19th century, more immigrants were arriving on all shores of the United States. In 1911, New York passed the Sullivan Act, essentially the same as any European anti-gun legislation, stating that the carrying of a handgun was illegal (in Europe, it was used as a form of keeping riots from becoming "too violent," while it was used in New York to keep immigrants from attempting to exert control over the state.) In 1923, New Hampshire passed a law to keep "designated peoples" from purchasing or carrying handguns (a distinction made for a reason), and residents of the state could only purchase handguns if they were deemed "acceptable" by a local elected official, typically a sheriff or justice of the peace. If the person applying for a permit was white, owned land (wasn't poor), and wasn't an immigrant, they could purchase a handgun and carry until the license expired one year later.
New Hampshire was the first to license as such, Vermont has never had licensing restrictions for carrying handguns.
Then in 1976, Georgia started the modern trend of permitting concealed carry of handguns, with more states adding the ability in the 80s and 90s, with events such as the Luby's massacre in Texas in 1995 spurring individual states to license concealed carry.

So to recap, Vermont and New Hampshire were the first to really allow concealed carry, with most states following about 50 years later.

In Michael H. Piatt's research of the Bodie , CA mines, he found ( based on newspaper accounts of violence) that most of the miners in the 1880's were carrying British Bulldogs, other cheap pocket-sized revolvers that went in a pocket: large pistols in open holsters ( like you see in Western films) seemed to have been rare. There were also shotguns and rifles around- as could be expected, as these could be used for both hunting and defense- and so it could be that a ban on concealed weapons was targeted ( hah!) at pistols. Bodie:The Mines are Looking Well.