This article examines the influence of community context and land use on the monthly odds of first birth in a society in the midst of dramatic fertility transition. The theoretical framework guiding our work predicts that proximity to nonfamily services should delay first births by creating opportunities for competing nonfamily activities and spreading new ideas that change expectations about family life. On the other hand, living in agricultural settings that provide opportunities for higher returns to child labor should speed first births. We use a longitudinal, multilevel, mixed-method data from the Nepalese Himalayas to test these predictions. The empirical results reveal that nonfamily services during childhood and during early adulthood both have important independent influences on the odds of first birth. Also, as predicted, a high density of agricultural land use affects the odds of first births in the opposite direction, speeding first births. This clear pattern of contrasting effects provides important new evidence of the contextual dynamics that produce watershed changes in postmarital birth timing.