The KRHDSS is a population-wide demographic and health surveillance system embedded in the community health structures of the Mariakani township in Kenya. It covers the mostly rural sections of the Kalolenina and Rabai sub-counties and consists of seven rural and three peri-urban community health units. At baseline, KRHDSS included over 78,000 residents in 13,778 households in 112 villages. In December 2018 (round 4), the median number of people per household was 5, women made up 51% of the population, 13.9% were children under 5 years of age, 2.6% were below 1 year of age, women of reproductive age (15 to 49 years) made up 23.0%, and adults (18 years and older) constituted 52.0% of the total sample.