Miscanthus is a promising bioenergy crop due to its high productivity and broad environmental adaptability to tropical and temperate climates. As important Miscanthus species such as M. sinensis and M. sacchariflorus are native to East Asia, implying more diverse Miscanthus genetic resources in this region, in this study, we collected about 300 Miscanthus accessions from East Asia, mainly in Korea. From the whole collections, 66 Miscanthus accessions representing geographical location and latitude were selected and tested through a 3-year field trial to investigate genetic diversity in their agronomic traits. Five agronomic traits associated with biomass production were assessed to investigate the relationships of agronomic traits with biomass yield and latitudes of locations where Miscanthus accessions were collected. Plant height, stem diameter, stem dry weight and heading date exhibited a significantly positive correlation with biomass yield with r= 0.465, 0.780, 0.817 and 0.450, respectively. Stem diameter (r= − 0.495), stem dry weight (r= − 0.393), heading date (r= − 0.914) and estimated yield (r= − 0.425) exhibited a significantly negative correlation with latitudes of the collection sites. The results of the study revealed the existence of considerable genetic diversity in agronomic traits in the Miscanthus accessions collected. The presence of a significant relationship between latitudes and agronomic traits suggests that accessions collected from different geographical latitudes will provide more genetically diverse materials for breeding. Therefore, the results of the present study can provide useful information and materials for Miscanthus breeding programmes.