The two characters that stand out in relation to this idea of being confined are Curley's wife and Crooks.
Curley's wife is told to keep to herself on the ranch. She is forbidden by her husband to socialize with the ranch hands. In their turn, the ranch hands shun Curley's wife, calling her a "tart" and sensing real danger in her. She is confined to a nameless role and to the house, able to expect conversation only at meal times when Curley and his father come to the house.
Crooks is isolated in the stables. Due to his skin color, he is given a room of his own off the stables and lives there alone. The other ranch hands live in the bunk house together. This physical division is a manifestation of the perceived and social divisions in the society of the time regarding skin color. It does not completely cut Crooks off from the rest of the men, but does confine him to an isolated living situation.