Background and Objectives: There are nearly 18 million family caregivers in the United States assisting an older adult in need of help. Identifying the caregivers in greatest need of support requires an understanding of the current social support networks available to family caregivers and whether specific groups of caregivers are at risk of having an insufficient support network. Research Design and Methods: We collected personal network data from a nationally representative sample of 66 family caregivers to persons with dementia (PWDs) in the United States aged 18 and older, including information on network members' support to the caregiver and help to the care recipient. Results: We found four common caregiving network types: large networks with many helpers; large networks primarily supporting caregivers; small, dense networks supporting both caregivers and care recipient; and small networks providing little help to either caregiver or care recipient. Gender, income, and geographic proximity of caregiver to the care recipient were significantly associated with caregiver network type. Discussion and Implications: This study suggests that there are different types of care and support networks available to caregivers to PWDs, and that the size and structure of networks vary considerably among demographic groups. As the population ages, a better understanding of the supports available to caregivers will be crucial for ensuring that caregivers are adequately supported, and caregiving needs of families are met.