Drawing on self-determination theory, this study advances our understanding of employees' experiences working from home (WFH). Specifically, we examine the effects of two social-contextual characteristics of WFH arrangements: whether employees voluntarily initiate their arrangement (WFH initiation) and the proportion of WFH employees in a unit (WFH density). We conducted multilevel analyses on a multisource dataset drawn from organizational HR records and two surveys of 2115 WFH employees in a Fortune 500 organization. Employees who voluntarily initiated WFH, rather than at their employer's direction, experienced higher job autonomy and lower isolation. WFH employees in units with a lower proportion of other WFH employees experienced higher job autonomy. WFH initiation and WFH density also had effects on several distal employee outcomes, including job satisfaction, organizational knowledge, and turnover intentions, through their effects on job autonomy and isolation. Our findings provide valuable insight into the experiences of WFH employees and call attention to two important, yet understudied, factors that shape these experiences.