The boundaries that mark gang territory are invisible but are known to people who live in those communities, because going to the wrong gas station or shopping mall could mean life or death.

In Los Angeles, streets, freeways, train tracks and the LA River form boundaries that many of us aren’t aware of. These are the boundaries of gang territories.

Back in the 1970s through the ‘90s, just wearing red or blue was contentious. It could have even made you a target.

The colors were, and still are in some parts of LA, flags for the Crips and Bloods, LA’s two dominant gangs.

And back then, the neighborhoods of South and East Los Angeles could have drawn their gang territories.

Things have cooled down a bit because of gang injunctions and safety zones. Lots of families have been priced out of their neighborhoods, moving further away from the urban core. And some of the action has moved off the street and gone online.

But, there are still certains parts of LA where gang borders form “invisible walls” that delineate who goes where and who does what.

Without clear markings, many LA residents don’t even know these barriers exist.

But these boundary lines are there and they carry a lot of weight for the residents who live among them.

Skipp Townsend was born and raised in the West Adams neighborhood of South LA. For many years he was a member of the Rollin 20s Bloods. He’s now a gang interventionist. And he says people in the communities where he works are well aware of the gang boundaries.

“You have to be aware of where you are at all times. I mean your life depends on it. So knowing what area you’re in, knowing what gas station you stop at, knowing what liquor store you’re in, even watching the cars as they roll down the street and being able to identify certain people. That’s always how a person stays alive, you know, just having your head on a swivel,” Townsend said.

And how do you find out where those boundaries are?

“Well the way I found out is being born and raised in L.A., so for people were born and raised in L.A. it’s just like automatic. It’s sort of like the deer and the gazelle that’s born in the wild, you know, they just know,” he said.

Gangs used to demarcate their boundaries with graffiti, which was more popular back in the ‘80s but is less popular now.

Instead, people who live in these communities need a mental map of where they are and aren’t allowed to go.

“But the perception is that we’re safe and sometimes we’re not,” Townsend said. “That’s why I say there’s a fear for parents and grandparents like, ‘man, do I even want you to come here? No, let me bring the kids to you.’”

“I have 12 and 10 year olds, I have to think about where they live or where they go to school, how they’ll get home, will I pick them up, will they play sports, if they play sports what park will they play sports at — all these things are important.”

Townsend isn’t alone in being concerned with the price you pay for living within gang boundaries.

“One of the really important things to think about is how the invisible borders or the claiming of space by a particular group can add costs we often don’t think about,” said George Tita, a gang criminologist at UC-Irvine.

“If I’m a young person growing up in a particular neighborhood and the closest movie theater or the closest shopping mall is claimed by a rival gang, whether I’m a gang member or not, I’m not going to feel comfortable, I’m going to have to spend more time on a bus, put more gas in my car, to travel to other areas,” Tita said.

“The turf basically serves as a warning to stay out of my area. You know, for forever and a day the quintessential gang homicide was the ‘where are you from?’ homicide, right. And this is where one individual would approach another and ask the question, ‘where are you from?’ In far too many instances nobody waited for a verbal answer. The answer came in the form of gunshots.”

Tita co-authored a study looking at where gang violence happens within territories. He found that they mostly happen on the borders.

“This is borrowed from the studies that are done on wolf packs and marking of territory. So we can think of marking the territory of a wolf pack similar to the graffiti and so you want to keep the rival outside the territory. You do it by patrolling these invisible walls,” Tita said.

Alex Alonso is an adjunct professor at Cal State University-Long Beach. He has mapped the overlay of gang boundaries on the map of Los Angeles.

“I noticed that the built environment does play a role in defining these gang neighborhoods. When I say the built environment I’m talking about primary roads, your large streets, your freeways, highways and train tracks and rivers. You know, very rarely are you going to find a gang turf on two sides of the L.A. River,” he said.

“You got Primera flats on one side, you got Frogtown on the other side and you’ve got various other gangs on both sides of the freeway. And the same with train tracks, the same with freeways, and the same with primary roads.”

And patrolling these invisible walls is no longer confined to the streets. It’s also gone digital. Twenty years ago Alonso founded StreetGangs.com, a venue for news, videos, history and chat forums all relating to gang activity across the US. Back when Alonso started interviewing gang members in the ’90s, he had to walk up to them on the street and introduce himself as a student at USC, which could get awkward. Now he mainly finds people through social media. And that’s where a lot of gang interactions have moved.

“It does kind of speed up the communications between me and gang members and between other gang members. But I don’t think it has this impact on violence that we’ve heard a few reports here and there, where people got into a Twitter beef or an Instagram beef and a shooting happened,” Alonso said.

“But I think these beefs are still natural beefs but it just so happens that rather than getting on the phone and talking, basically social media and the Internet is the phone now. The beef is now being facilitated through a different manner, through a different tool.”

As more conversation between gang members happens in the digital space instead of the physical space, does that make gang borders less relevant?

“The physical space is certainly important but this digital space is now giving law enforcement a new avenue to use, a new tool to investigate. And people have to realize the LAPD, the L.A. County sheriff, they’re on your Facebook page, they’re on your Instagram page. They’re watching everything,” Alonso said. “I don’t think it takes away from the physical space. The physical space is what gives the gang its existence. Without that physical territory you pretty much don’t have an identity.”