Homes are infested from time to time by sugar ants. These may also be called Argentine ants, pharaoh ants or piss ants in some parts of the country. They are small, black and difficult to control. While you can spend considerable time and money on sprays that instantly kill the ants, you will not completely rid your space of them unless you manage to kill their queen, which never comes out into plain sight but lives instead in the ant hill or den from which the other ants come. Ants will carry ant bait back to their home, where it will be consumed by other ants, including the queen, and poison the whole lot of them.
Prevention helps. Keep a clean kitchen and bathrooms to reduce the attraction of these ants. Sugar ants go for anything sweet. Don't leave dirty dishes overnight.
Stop using insecticide sprays on the ants. It kills them too quickly and the nest just goes on. The queen will only lay more eggs, and parts of the ant colony may move to another part of your property, multiplying the problem.
Set out both liquid and gel ant baits, following the package instructions for use. Keep them away from areas where children and pets play, as they can be hazardous to humans and animals if ingested.