The scourge in California (and probably all along the West Coast up to Alaska) is the so-called Argentine ant. It's theorized that it's all one giant colony, with multiple queens. So different nests don't fight with each other, and the ants push out navie species.
I have develeped a particularly diabolical way of getting even with the ants. I have a lot of potted plants around the outside of the house. Periodically I find that the ants have moved into one and started nesting there. My solution is to fill a big barrel (a 16 gallon muck bucket works well) with water, and then place the infested pot in it. As the ant swarm out to try to escape, I hit them with a suitable insecticide (I prefer the cedar oil and/or mint oil based "safe" sprays). If there are queens and brood in the plant pot, it really does seem to put a dent in the ant activity, at least for a little while. But in reality, the war with the myrmicidian terrorists is one that can never be won. We win little battles, maybe keep our homes mostly ant-free most of the time, but barring some devastating ant disease or natural predator, the Argentines will always bounce back.