The purpose of this methods article was to describe and evaluate outreach and engagement strategies designed to initially build county-wide awareness and support for the National Children's Study (NCS or the study) and subsequently to target the segment communities where recruitment for the study occurred. Selected principles from community outreach, social marketing, and health care system and personal referral formed the foundation for the strategies. The strategies included a celebration event, community advisory board, community needs assessment, building relationships with health care providers and systems, eliciting a network of study supporters, newsletters, appearances at local young family-oriented events (health fairs, parades), presentations to local community leaders, community forums, “branding” with assistance from a women-owned local marketing firm, and mailings including an oversized, second-touch postcard. Six months after study launch, approximately 4,600 study-eligible women were asked in a door-to-door survey if and how they became aware of the study. On average, 40% of eligible women reported being aware of the study. The most frequently cited strategy to cultivate their awareness was study-specific mailings. Awareness of the NCS increased by 7.5% among those receiving a second-touch postcard relative to controls (95% CIs [4.9, 10.7] z = 5.347, p < 0.0000, d = 0.16). Community outreach and engagement strategies, in particular the oversized postcard as a second-touch effort, may be used effectively by researchers for participant recruitment and by public health nurses for delivery of important population-focused messages.