On Valentine’s Day 2013, the heads of the Chicago Crime Commission and the Chicago office of the U.S. Drug Enforcement Administration named infamous Mexican drug lord Joaquín “El Chapo” Guzmán as the city’s Public Enemy No. 1.

The timely label, occurring 84 years after gangster Al Capone first earned it following the St. Valentine's Day Massacre in 1929, lasted only a year as Guzmán was arrested in Mexico the following February, but the imprint his organization made – and continues to make – on Chicago has helped turn the U.S.’s third-largest city into one of the nation’s largest drug trafficking hubs, replete with the violence and related crimes that come with that designation.

“Sinaloa Cartel traffickers sit on the top of the pile, and they feed down all the way to the street level dealers,” Dennis Wichern, special agent in charge for the Drug Enforcement Administration’s Chicago field division, told Fox News Latino.

The drug trade in Chicago has helped fuel pervasive gang violence that has resulted in a quickly rising homicide rate. Chicago ended 2014 with 425 murders, and this year the city had seen 30 slayings by the end of January.

New York may have the famed five families of the Mafia, and Los Angeles is the cradle of the Bloods and the Crips, but Chicago remains gangland capital in the United States.

From Capone and his North Side Gang rival, Hymie Weiss, in the 1920s to the Vice Lords and Latin Kings in the 1950s to biker gangs like the Outlaws that emerged in the city’s suburbs, the Second City has bred some of the U.S.’s most dangerous and famous criminals over the past century.

Now, however, the heavy-hitters from the criminal class appear to be moving to Chicago from south of the border and using the city’s ever-growing Mexican population to camouflage themselves and recruit new members.

“It’s not a new phenomenon up here in Chicago,” Wichern said. “Like any population, there will be a small element that gets involved in criminal activities.”

Cook County police say that the neighborhoods of Pilsen and Little Village, both of which are about 82 percent Hispanic according to Census data, have become hubs for Sinaloa Cartel associates who traffic heroin, cocaine, marijuana and methamphetamine across the city and – with easy access to the Stevenson, Dan Ryan, and Eisenhower Expressways – across the country.

Chicago is one of the U.S.’s largest interior cargo ports, the world’s third-largest handler of shipping containers, and is located along the Burlington Northern Santa Fe rail line. It also sees 1.5 million tons of imports and exports a year go through O’Hare International airport alone in a year.

The city has 1.3 billion square feet of warehouse property – one of the largest concentrations of industrial space in the U.S. – which offers plenty of space for traffickers to hide their product.

“It’s a huge distribution center with so many interstates and train lines that [traffickers] can run their products out of the city,” Adam Isacson, a senior associate for regional security policy at the Washington Office on Latin America told FNL.

The biggest cash earner for the Sinaloa Cartel – which controls about 45 percent of the entire U.S. drug market – in Chicago is heroin. Many people addicted to painkillers have switched to heroin both because it's cheaper than prescription pills and because purity levels of heroin have risen in recent years.

In Chicago, the largest increase in heroin overdoses has occurred in the suburban areas surrounding the city, according to the DEA’s 2014 National Drug Threat Assessment.

The Mexican cartels, especially Guzmán’s Sinaloa group, have also found heroin to be very profitable as they deal with falling cocaine consumption and marijuana legalization in parts of the United States. Once known as small-scale producers of low-quality heroin, the Mexican cartels are now refining opium paste into high-grade, white heroin that sells for a fraction of the cost that it did a few years ago.

“Heroin is making a ridiculous comeback in the U.S. right now,” Isacson said. “It’s not that low-grade, black tar stuff anymore… It’s now so pure you don’t even need a needle to get high because you can just snort or smoke it.”

The DEA's 2014 National Drug Threat Assessment found that while Afghanistan is by far the world's largest producer, it largely sends its heroin to markets in Europe and Asia. While half the heroin found in the United States now comes from Mexico, up from 39 percent in 2008.

The Sinaloa cartel's near-monopoly on the drug trade in Chicago has led to skyrocketing levels of violence among lower-level drug gangs throughout the Windy City and left drug enforcement officials in the Midwest struggling to catch up.

Officials at the DEA admit that winning the drug war is not something that is entirely feasible, but they did highlight a number of recent high-profile arrests and convictions that put dents in the Sinaloa Cartel's armor.

The DEA in Chicago has a very strong case against Guzmán  if he is ever extradited to the U.S. – something that is being debated in Mexico right now. Also last week two major capos-turned-informants in Sinaloa’s Chicago organization were convicted of running a $2 billion drug ring. That was quickly followed by a federal indictment of nine alleged drug traffickers connected to the Mexican crime group.

“The DEA is out there banging away and making arrests every day,” Wichern said.

Even so, Wichern added, it is difficult to keep up with the evolving tactics of the cartels and the market which they cater to.

“The game is always changing out there,” he said.