Approximate map of gang territory
There are eight major gangs in Grand Theft Auto: San Andreas: four in Los Santos, three in San Fierro, and one in Las Venturas. Of those, several are divided into sets.
San Andreas Gangs[]
Rockstar North conducted massive amounts of research before developing the gangs of San Andreas, research that involved talking to DJ Pooh, Mister Cartoon, Estevan Oriol, and hundreds of other well-known faces. Gangs play a much larger role than they did in Grand Theft Auto: Vice City.
Firstly, the number of gangs has increased. As well as having the large, dominating gangs, there are also smaller, more local gangs. Generally, gangs cause a bit more trouble than they did in previous titles, as they are toppling cars, crowding streets and using various new methods of attack. GTA San Andreas gives the player the ability to "take over" areas of the map, and recruit members into their gang to help defend themselves.
Gang members are recognised by their clothing, tattoos, and hand signs. These are useful for two reasons - they allow the police to identify a gang set or victim, and they also allow gang members to interact with one another. Each gang has its own territory, indicated by street warnings, wall graffiti, or simply violence. In Los Santos, two of the four gangs are split up into different "sets". This is bad, because not all sets get along, but also good, because there's always plenty of backup available.
Gang Wars & Territory
Winning territory is done through the means of gang wars. One must enter an area that they wish to control, and kill every opposition member in sight. Killing three members on foot will provoke a gang war, and the area under attack will flash red on the radar. The opposition attack in three waves to defend their land. Keep a close eye on the radar, and watch where the attackers are coming from. They may attack unexpectedly or in large numbers, so having a plentiful supply of health and armor, as well as plenty of ammo for weapons before starting the war is recommended. If possible, shoot from long distances or from rooftops.
Sometimes, even cars will turn up (within larger territories), with gang members inside doing a drive-by on the player. Once the player survives the three waves, the area is theirs. It is now highlighted with a green color on the map. Other gangs may try and take the player's territory, and it's up to themselves to defend it. Gang wars and territories are introduced during Sweet's mission Doberman. After the mission The Green Sabre, CJ no longer has the ability to win new territory, or defend his own. The feature returns during the mission Home Coming.
There are cheats which allow the player to put all gangs from all over San Andreas onto the streets, usually leading to violent encounters.
Recruitment
Recruiting homies is done through a special command performed based on controls, such as pressing 
whilst targeting a member (PlayStation versions), targeting a member and pressing 
(PC), or aiming at a gang member and tapping the "recruit" button (mobile versions). CJ can recruit a maximum of seven members at any given time. The maximum number of recruits depends on CJ's respect level. A Coach will hold all seven members, whereas a typical car will carry a maximum of three.
Pressing (on PlayStation versions) or (on PC) while CJ's homies are close will have them follow him. Pressing 
on the PlayStation versions or 
on the PC version will make them stay put until told to do otherwise. Holding down the very same buttons will disband CJ's gang. The gang can also be disbanded by simply going far away from them.
CJ's homies will return fire to those who attack him, and shoot at other gangs, cops, SWAT members, FBI agents and the military. They will also participate in drive-by shootings. However, the homies aren't very reliable, so one should not depend on them too much. They can, however, draw fire away from CJ.
On the PlayStation versions, pressing 
while CJ has the camera in his hand can lead to a homie taking a picture of him. The same thing can be achieved on PC by using the 
button.
There are cheats that allow the player to recruit any pedestrian, and not just homies. There are two such cheats: one that gives the recruits a pistol, and one that gives them a Rocket Launcher. The pedestrians are not very good at manning the rocket launcher, however.
Grove Street Families[]
Grove Street Families
The Grove Street Families are a black/Afro-American street gang in Los Santos and used to be the most powerful gang in Los Santos, but have been silenced over the past few years by drugs, internal disagreements and their sworn enemies, the Ballas. The Seville Boulevard Families (controlling only a small area in south-east Los Santos) and the Temple Drive Families (controlling western Los Santos territories) have split from the Grove, so just because they're wearing green doesn't mean they are necessarily allies. Whilst these events took place, the Vagos and Ballas took over. Everyday, Grove Street gets weaker, and the Ballas get stronger. Grove Street OGs include Sweet (Sean Johnson), Big Smoke (Melvin Harris, formally), Ryder (Lance Wilson, formally) and CJ (Carl Johnson).
The families must re-unite if they are ever to rise again. The Grove Street Families control the areas of Ganton, Playa del Seville, Temple, and Santa Maria Beach. Later in the game, they also take over Glen Park and Idlewood.
They are involved in gang banging, gang warfare, gang-related homicide, murder, gun running/arms dealing, street violence, robbery, protection, and vandalism. Unlike the Ballas and Vagos, they are heavily against drug dealing. They are either unarmed or carry 9mm pistols and Tec-9s. They may also carry Desert Eagles, SMGs and knives if all 100 gang tags in Los Santos are sprayed over. If gang members are unarmed when they are recruited to the gang, they automatically receive a 9mm pistol. They can be seen drinking beer and smoking marijuana while hanging in groups. They drive Greenwoods, Savannas and Voodoos and listen to Radio Los Santos.
When CJ comes by the jail to pick up Sweet, his brother, some of the GSF gang members have either become addicted to drugs, gone into hiding, left the gang, defected to the Ballas, or were employed by Big Smoke as cash couriers, in addition to drug dealers having a stronghold in Ganton and Grove Street.
Ballas[]
The Ballas are the largest and most powerful black/Afro-American street gang in Los Santos and have a bitter rivalry with the Grove Street Families. The Ballas come in four sets - Front Yard Ballas, Rollin' Heights Ballas, Kilo Tray Ballas and the Temple Drive Ballas. The Front Yard Ballas are Los Santos' most notorious drug dealers, Grove Street's biggest rivals and control the areas of Idlewood and East Los Santos. The Rollin Heights Ballas act as backup and control the area of Jefferson, and some parts of Willowfield and East Los Santos. The Kilo Tray Ballas only control the area of Glen Park, and some parts of Willowfield. The Temple Drive Ballas are a much smaller set based in Verona Beach and formerly Temple prior to 1992 (hence their name) until Grove Street took it over. The Ballas eventually lose their Glen Park and Idlewood territories to the Grove Street Families.
The Ballas are battling with their rivals (the Vagos, Varrios Los Aztecas, and especially the Grove Street Families) to control South Central Los Santos. The Ballas have been around since the 1970s - involved in drug dealing, gang banging, protection, murder, gang warfare, gang-related homicide, robbery, street violence, arms dealing, vandalism, degeneracy, but mainly, the cocaine trade. They have ties with Big Smoke and the Loco Syndicate for drugs (mainly crack cocaine), and the Russian Mafia for weapons.
They can be seen drinking beer and smoking marijuana while hanging in groups, their gang color being purple. They are either unarmed or carry Micro SMGs and 9mm pistols, but when in gang wars with them, they have AK47s, SMGs, Shotguns, 9mm pistols, Micro SMGs, and Baseball Bats. In some missions, they are equipped with Tec-9s. They can be seen driving Tahomas and Majestics, and their favorite radio station is Bounce FM.
Part of their strategy to wipe the Grove Street Families out is to spread crack cocaine into their territory, which they primarily get from Big Smoke. Later in the game, they receive more crack cocaine from Big Smoke in return for protection of his drug empire.
Varrios Los Aztecas[]
Varrios Los Aztecas
The Varrios Los Aztecas are a small-time Latin/Mexican Los Santos street gang based in the barrios of El Corona and Little Mexico in addition to Unity Station - a popular meeting spot for the Aztecas, distinctly recognized by their turquoise bandanas. They have a major rivalry with the Los Santos Vagos and San Fierro Rifa, but are also enemies with the Grove Street Families and the nearby Ballas. They are heavily involved in gun running/arms dealing, street violence, gang banging, gang warfare, gang-related homicide, murder, robbery, vandalism, illegal street racing, and carjacking, but are slowly diminishing. The Varrios Los Aztecas are traditionally anti-narcotics and part of their identity is heavily involved in the lowrider culture.
They can be seen drinking beer and smoking marijuana while hanging in groups. They are either unarmed or carry 9mm pistols and Micro SMGs. Gang veterans include Cesar Vialpando, Jose, Sunny, Gal and Hazer. They drive Broadways, Hermeses and Glendales, and their favorite radio station is Playback FM.
Despite the fact that Cesar, a high ranking member (who may also be the leader), is a friend of the protagonist, this gang will be hostile towards the player and may attack CJ and his gang unprovoked.
Los Santos Vagos[]
Los Santos Vagos
The Vagos are a large and powerful Mexican Los Santos street gang that sport yellow bandanas, and occupy a majority of the far north and east areas of Los Santos, namely Las Colinas, East Beach, and Los Flores. This Hispanic gang are sworn enemies of the Varrios Los Aztecas, but are also enemies with the Grove Street Families and Ballas. They are known to attack in large numbers. Heavily involved in drug trade (especially crack cocaine), gang banging, street violence, arms dealing, gang-related homicide, gang warfare, murder, protection, robbery, and vandalism. Much like the Ballas, the Vagos have a major involvement in Big Smoke's crack business, offering protection and earning drugs in return. It is the only situation in which the two gangs cooperate.
They can be seen drinking beer and smoking marijuana while hanging in groups. They are either unarmed or carry 9mm pistols. During a gang war, they are also equipped with Micro SMGs, SMGs, AK47s, shotguns, and baseball bats. In some missions, they are also equipped with Tec-9s and M4s. They drive Hermeses, Oceanics and Tornados, and their favorite radio station is K-DST.
They were strong enemies with the San Fierro Rifa until they joined the narcotics business. From then, the Rifa and Vagos often dealt with narcotics.
San Fierro Rifa[]
San Fierro Rifa
The San Fierro Rifa are a Mexican/Hispanic San Fierro street gang control the areas of Garcia, Doherty, King's, and Battery Point. They have become a major hub in the international drugs trade (especially crack cocaine). They are also involved in gang banging, street violence, gang-related homicide, gang warfare, robbery, murder, protection, arms dealing, and vandalism.
They initially held hostility towards all Mexican gangs in Los Santos, but cooperated with the Vagos when they joined the narcotics business - although they still maintain a very strong rivalry with the Varrios Los Aztecas. T-Bone Mendez is the leader of the Rifa. They are either unarmed or carry just 9mm pistols and can be seen drinking beer or smoking blunts while hanging in groups. They can also be identified by their turquoise bandanas, much like the Varrios Los Aztecas (but not to be confused with them, as they have a strong violent rivalry).
They are the least harmful gang in the game, mostly due to the lack of Micro SMGs. They drive Sabres, Blades and Stallions, and their favorite radio station is K-Jah West. They're known for running away from CJ when they are feeling threatened, but will often question CJ about his gangbanging status. If the player chooses to respond positively - they will attack.
Early-on, they act as protection for the Loco Syndicate until they are wiped out. Later, they are hired by Big Smoke for protection of his crack empire in return for drugs.
San Fierro Triads[]
San Fierro Triads
The San Fierro Triads are a Chinese San Fierro based criminal organization helped along by Wu Zi Mu, a blind gentleman, and led by Ran Fa Li. The Triads operate the Four Dragons Casino in Las Venturas, but their main place of work is Chinatown. There are two sets of Triads - The Mountain Cloud Boys, operated by Woozie, and the Red Gecko Tong, led by Ran Fa Li. There was also a third set - the Blood Feathers that were wiped out by the Da Nang Boys.
They are involved in gang warfare, murder, smuggling, extortion, bribery, loansharking, gambling, and illegal street racing. It is revealed that the Triads are against drug dealing (especially crack cocaine).
The Triads are currently in a major war with a Vietnamese street gang known as the Da Nang Boys. They are also on unfriendly terms with the San Fierro Rifa, but are not engaged in a full-out war with them - mainly due to their drug involvement. Because of this, the Triads also have a strong disliking of the Loco Syndicate as well.
They are either unarmed or carry AK47s and 9mm pistols. In the mission Pier 69, they also carry Tec-9s. They can be recognized by all black smart/suit clothing. They drive Stratums, Elegys and Sultans and their favorite radio station is SF-UR.
Da Nang Boys[]
Da Nang Boys
The Da Nang Boys are a Vietnamese street gang based in San Fierro, preparing a full move to the United States. They control the dockland/bay area in Easter Basin and parts of Esplanade North, often causing violent disturbance. They're currently at a major war with the San Fierro Triads.
They are extremely violent with major interests in protection, smuggling, human trafficking, gang warfare, and arms dealing/gun running. They are either unarmed or carry 9mm pistols and Micro SMGs. In some missions, they also carry knives, shotguns, Tec-9s, and AK47s. They drive Buccaneers, Tampas and Mananas and their favorite radio station is Bounce FM.
Not much else is known about the gang, but it is possible that the Snakehead is the leader in the United States.
The Mafia[]
The Mafia in Grove Street.
The Mafia are a series of Liberty City-based Italian mob families operating in Las Venturas, and each of them have a stake in Caligula's Casino. The Sindacco Crime Family want to do business with the Leones, and this involves Salvatore pledging five million dollars to the Sindaccos. Both gangs argue over who should run the casino, and so Ken Rosenberg (once working with the Forellis down in Vice City) is put forward as a neutral party. Ken is in the middle of the three mob families, so if one attacks the other, Ken will most likely be the target. The Sindaccos are represented by Johnny, and the Forellis continue causing trouble for the Leones. The Triads have opened a new casino at the opposite end of The Strip, which will likely feature as competition for Caligula's.
They don't normally appear on the streets like other gangs do. However, by using cheats, they can be seen either unarmed or carrying Desert Eagles and 9mm pistols. They drive Sentinels, Admirals and Feltzers. Their favorite radio station is apparently WCTR.
Other Gangs[]
- The Shining Razors and Butterfly Children are two other Vietnamese gangs mentioned by The Truth to have a presence in Easter Basin, San Fierro. Unlike the Da Nang Boys, they are never seen and play no role in the storyline.
Three survivalists with rifles and a shovel.
- The Survivalists are a group of hillbilly farmers who own and operate a farm in Flint County. They are armed with rifles and shovels and they use tractors and Waltons for transportation. Other vehicles they own are a combine harvester and a lawn mower. They are enemies with The Truth who describes them as "right wing fascists".
A San Andreas Biker on a Freeway.
- The San Andreas Bikers are a loose group of bikers active in rural San Andreas. It is unknown if they are an outlaw motorcycle club or different independent bands of bikers. They wear the same riding club logo on the back of their vests, but they lack a clubhouse, emblem and full patch. They ride Freeways, Wayfarers and FCR-900s. They are often found riding alone and have no territory.
Russian Mafia mobsters shooting.
- The Russian Mafia is a Russian criminal organization with a small role in the game, having presence in Los Santos. They use BF-400 bikes, Sultans, Banshees and a Packer. They only appear in a few missions, being attacked by Carl Johnson and Big Smoke in the Atrium building in Commerce. They also seem to collaborate with the Ballas, helping them get weapons. Moreover, they collaborate with the Ballas, as well as the Los Santos Vagos and San Fierro Rifa in an attempt to defend Big Smoke's Crack Palace in the final mission, but fail to do so.