Mountain rangelands are critical resources for mobile pastoralists, and they provide benefits to humankind broadly. Yet mountain pastoral social–ecological systems (SESs) face challenges that affect both mountains and rangelands. Herders' traditional ecological knowledge (TEK) underpins their adaptive strategies and serves as a resource for future adaptation. This holistic case study of Ilemchane transhumant herders in Morocco's High Atlas Mountains applies a simple framework to explore how herders' biophysical TEK, practices, and institutions interrelate and how climate and social changes affect the SES. Using participant observation, interviews, and surveys, we find Ilemchane climate, plant, and ecological knowledge shape their practices and institutions, which in turn reinforce or alter TEK. Building on a recent synthesis of mountain SES, we identify a paradox of remoteness, wherein Ilemchane remoteness both maintains traditional transhumant culture and TEK and threatens it. Overcoming this paradox may require internal organization, collective action, and external support.