High rates of forest conversion and fragmentation have placed many endemic species in the rainforests of Sri Lanka under threat. Ceratophora is an endemic and endangered/critically endangered genus of lizards containing five species, and C. aspera has the widest distribution spanning four forest regions, making it an ideal candidate species for broader conservation management projects. The goal of this project is to study the phylogeography of C. aspera across its range in the forests of southwest Sri Lanka to assess the genetic variability of the remaining populations across two lowland areas, the submontane zone (Sabaragamuwa Hills), and the montane forest zone (Central Hills). Analyses of genetic data are important for understanding the relationships between geography and genetics and to determine where populations are connected and fragmented. During the2018 and 2019 field seasons, tail clippings were collected from wild lizards. In the University of Washington's Biology Department, DNA sequencing of mitochondrial DNA (ND4 gene) was used to measure genetic diversity within and among populations, and to estimate phylogenetic relationships. Genetic diversity is highest (6%) between the population from Hiyare (lowlands) and the Sabaragamuwa Hills (submontane zone). There is also strong evidence for highland and lowland groups. Populations from Hiyare, Sinharaja and Gilimale show no intra-population variation. Sri Lanka has pledged to reforest 200,000 ha of degraded forest to create forest landscapes under the Bonn Challenge, and to increase forest cover to 30% unde the Paris Climate Agreement. Phylogeographic profiles of endemic species, such as C. aspera, are critical for forest restoration strategies as they identify priority