Pet Ground Squirrels need a very large cage such as those designed for ferrets or rats with multiple levels. Suggestions include the Savic Royal suite 95 or the Rosewood Aurora Cage. Since they enjoy burrowing some keepers include a large glass tank within in this that can have a foot of substrate for burrowing in. Male Richardsons ground squirrel can be kept alone if needed but females must be kept with company.
Ground squirrels need plenty of material for constructing nests and benefit from a very large solid based wheel. They can also have a litter tray designed for ferrets.