Δ14C values of leaves of deciduous trees provide a means to map the regional-scale fossil fuel ratio in the atmosphere. We collected a batch of ginkgo (Ginkgo biloba Linnaeus, a deciduous tree) leaf samples from across Korea in the month of July in both 2010 and 2011 to obtain the regional distribution of Δ14C. The Δ14C values of the samples were measured using accelerator mass spectrometry (AMS) at the Korea Institute of Geoscience and Mineral Resources (KIGAM). The average of the Δ14C values from clean air sites in Korea in 2011 measured slightly lower than the average of Δ14C values in 2010. Distribution maps of Δ14C of 2011 and 2010 in Korea were made based on a series of Δ14C values of ginkgo leaf samples from Korea using the Geostatistical and Spatial analyst tools in ESRI's ArcMap software. The distribution maps of Δ14C showed that Δ14C values in the western part of Korea are lower than those in the eastern part of Korea. This is because the western part of Korea is densely populated and contains many industrial complexes, and also because westerly winds from China, containing CO2 from fossil fuel use, blow into Korea. We compared the distribution maps of 2010 and 2011 and tried to find traces of the Fukushima power plant accident in Japan.