Research Findings: Many young children spend crucial developmental years in informal, home-based child care (HBCC) settings, but parents and others share concerns about HBCC quality. We applied the ecomap method in a descriptive study of racially, ethnically, and linguistically diverse informal caregivers and parents to capture their informal caregiving arrangements, social networks, and social supports. For the parents in our study, informal child care was a flexible, affordable, and readily accessible child care option. For caregivers, informal care provided opportunities to help family and friends and to earn extra income. Social networks were characterized largely by relationships with family and friends, and social supports tended to be strong and mutually beneficial. Practice or Policy: We found that ecomapping is an engaging and flexible method of capturing and understanding complex child care arrangements and social networks in HBCC settings. As a research tool, ecomapping can help improve the quality of care in informal settings by identifying and meeting the needs of parents and HBCC providers and informing program development and delivery strategies.