Reliable information on the extent and spatial distribution of mangroves has not been available for China. To create a map assessment of the mangroves for this region, an object-oriented classification technique was applied to Landsat-5/7 imagery at 30 m spatial resolution and verified using ground-truthing. Areal statistics for the mapped mangroves revealed that there were 20778 ha of mangroves located along the southeast coast of China. Extensive tracts of mangrove were found in Guangdong, Guangxi, Hainan, and Fujian Province (9289, 5813, 3576, and 1023 ha, respectively). Based on ground-truthing, the overall accuracy of our mangrove map was 92.6 % and the Kappa confidence was 0.85. Knowledge of the status and distribution of mangroves is important for advancing their management and conservation in China.