The United States was founded on July 4, 1776, when the British colonists on the East Coast went up in arms against the distant British Crown 10,000 miles away in Great Britain. After eight years of fighting, in 1783 they were realized as an independent nation and inherited all of the original thirteen colonies that Great Britain had. By way of purchase, conquest, or agreements, the USA took over all of the lands from the East Coast to West Coast, with significant obstacles being the War of 1812, the Texan Revolution, Plains Indian Wars, and Mexican-American War. By 1959, the USA had 50 states, including the icy lands of Alaska and the sunny islands of Hawaii, both non-contiguous states quite a distance away from the mainland.
Before the Manifest Destiny, the USA was inhabited primarily by British and Scots-Irish immigrants, but with the purchase of Louisiana (US Midwest), a significant French population was gained, and when the USA took over New Spain from Mexico, they gained a large Hispanic population on the West Coast. In the early 1900s, as other countries had troubles adapting to the new generation, immigrants came to the USA from across the globe, including Irishmen, Italians, Russians, Jews, and Chinese. The USA became a melting pot, but with lands of promise came overpopulation, and many people had to resort to criminal activities.
In the early 1900s, gangs started to form, usually within certain ethnic groups; the Irish Mob had been created in the 1840s with the potato famine causing Irishmen to flee to New York and Boston. Now, the Italian Mafia, Jewish Mob, Russian Mafia, and other ethnic criminal organizations began to form. They fought each other over gambling, and soon, heroin and narcotics were introduced to the USA. The Mafia Golden Age lasted from 1927 until the 1970s, when Cubans and African-Americans started to form their own cocaine gangs. The Ballas, Bloods, Crips, Grove Street Families, Vagos, Mexican Mafia, Montana Cartel, Colombian Cartel, and other street gangs (not "organized" like the Mafias) started to rise to power through the drugs trade. By the 1990s, the Mafia were near eradication as the law closed in, while gangs took over Los Angeles as New York fell to the law. As of 2013, gangs are the predominant of the two types of criminal organizations, with the most-dangerous cities being East St. Louis, Flint, Youngstown, New Orleans, Chicago, and Los Angeles.
However, by the 2000s, new types of gangs began to form: methamphetamine cartels. One of them, led by former professor Walter White, gained prominence after destroying Gus Fring's operations and also creating a fortune out of cooking meth from the New Mexico desert. Other meth gangs include Trevor Phillips Enterprises, the Irwin Brothers, and the O'Neil Brothers. These organizations tend to inhabit the Midwest.
Finally, there is the last type of gang, more rowdy than all of the others: biker gangs. The Hells Angels, The Lost MC, and Angels of Death have had long-lasting traditions of messing up public life by dealing drugs, crashing parties, taking part in illegal street races, having biker conventions in Australia, listening to hardcore rock music, and gangbanging. They are in pretense of being "social clubs", while they are no better than the Crips or Bloods; in fact, they may well even be worse.
As of 2013, the government have taken steps to eliminate crime by using gang and drug rehabilitation centers and awareness programs, and many of the Mafia have joined the Witness Protection Program. Gang members are still very strong in the US West in LA, and deal drugs, but on the East Coast, crime has been limited. The most-dangerous city is Flint, Michigan, with the highest murder-per-population ratio of all US cities.