Lions do actually live in groups, they are called prides. These groups are relatively large, consisting of a total of up to 10-15 lions including related females and their cubs and one or two males. They work together in hunts in order to be more effective and share in the kills.
There are lions that do not live in these groups or are excluded and then are found as nomads singly or in groups of two.
They often prefer to live in grasslands or other similar areas where they can take advantage of their coloring and other factors to sneak up on their prey as they are not capable of long bursts of speed to catch prey.