As onchocerciasis programs in Africa shift from a paradigm of control to one of elimination, there is a need to determine whether transmission is ongoing in previously-untreated areas. To do so, there is a need to develop a mapping strategy that is rigorous enough to detect low levels of ongoing transmission while also using resources efficiently. A multi-country operational research study was conducted comparing sampling in purposively-selected communities, random sampling in randomly-selected communities, and random sampling in the schools in which the majority of children from the randomly-selected villages attended. In Malawi, quota sampling was used in purposively selected communities. Three districts were included in the study: Chitipa, Dedza, and Karonga. Chitipa had never previously undergone treatment with ivermectin, whereas Dedza and Karonga had previously undergone ivermectin/albendazole treatment for lymphatic filariasis. In Chitipa, the highest prevalence in a purposively-selected community was 0% by Ov16 rapid diagnostic test (RDT) and 2% by SD Bioline Ov16 ELISA, whereas the mean prevalence from random sampling was 0.1% by RDT and 5% by ELISA. In Dedza, the highest prevalence in a purposively-selected community was 2% by RDT and 36% by ELISA, whereas the mean prevalence from random sampling was 0.6% by RDT and 7% by ELISA. In Karonga, the highest prevalence in a purposively-selected community was 0% by RDT and 8% by ELISA, whereas the mean prevalence from random sampling was 0.1% by RDT and 9% by ELISA. Interpretation of results in this context is still ongoing. (2020-11-03)