Iitate Village is located 30–45 km northwest of Fukushima Dai-ichi Nuclear Power Plant (FNPP) and suffered serious radioactive contamination by the FNPP accident in March 2011. Our team has been conducting car-borne radiation surveys on main roads in Iitate Village since the end of March 2011. The average ambient radiation dose rate of 0.31μSv/h was obtained by the last car-borne survey on April 1, 2023, which was 1/35 of the initial value of 10.8μSv/h on March 29, 2011. Meanwhile, the aerial monitoring data taken by the Nuclear Regulatory Authority Japan (NRA) in October 2022 using helicopters at 300 m above ground indicated an average ambient dose rate of 0.82μSv/h in Iitate Village. The difference between our car-borne survey and the aerial monitoring reflects heavy contamination of the forest occupying 75% of Iitate Village without decontamination. Future perspectives of areas contaminated by the FNPP accident are given based on NRA’s aerial monitoring data in October 2022. In 2122, that is, 100 years later, the area size of significant cesium-137 (137Cs) contamination more than 40 kBq/m2 will remain 350 km2, while the serious contamination more than 500 kBq/m2 will almost disappear.