Fukushima's evacuation zones, 2011 to 2026

The first zone was a circle. On the night of 11 March 2011 the government ordered an evacuation within 3 km of Fukushima Daiichi and told people between 3 and 10 km to stay indoors; at 05:44 on 12 March the evacuation widened to 10 km, and at 18:25 to 20 km. On 15 March people between 20 and 30 km were told to shelter indoors, and on 21 April the 20 km radius became a no-go zone. Contamination, however, did not fall in circles. April monitoring found high dose rates beyond 20 km, around Iitate, and areas where the cumulative dose over a year could exceed 20 mSv were added. According to Fukushima Prefecture, as of 23 April 2011 the designated zones covered about 12% of its 13,783 km².

From 2012 the map stopped being drawn with a compass and started being drawn with dose. The evacuated area was reorganized into three categories based on the estimated annual cumulative dose as of March 2012: areas preparing for the lifting of the order, below 20 mSv a year; restricted habitation areas, above 20 mSv; and the Difficult-to-Return Zone, above 50 mSv, where the dose could still exceed 20 mSv even six years later. After that reorganization the area under evacuation orders peaked in August 2013 at 1,150 km², according to the Reconstruction Agency. That figure and the 12% from 2011 measure different things: one counts every zone designated in April 2011, the other only the area under an evacuation order.

Lifting followed the same logic. The 20 mSv a year threshold that decided who had to leave became the criterion for going back, together with decontamination and infrastructure repair. In July 2016 orders were lifted in Minamisoma and Joban Line trains ran again between Haranomachi and Odaka. On 1 April 2017, with most orders outside the Difficult-to-Return Zone already lifted, the evacuation zones added up to 371 km², 2.7% of the prefecture. By March 2020 orders had been lifted everywhere except the Difficult-to-Return Zone, and since then what remains under an order is essentially that zone.

Inside the Difficult-to-Return Zone, a May 2017 amendment to the special reconstruction law allowed towns to mark out Specified Reconstruction and Revitalization Bases, decontaminate them and reopen them ahead of the rest. Six municipalities had them approved between September 2017 and May 2018: Futaba, Okuma, Namie, Tomioka, Iitate and Katsurao. The first orders were lifted in March 2020 around Futaba, Ono and Yonomori stations; Katsurao and Okuma followed in June 2022, Futaba on 30 August 2022, Namie on 31 March 2023, Tomioka on 1 April, Iitate on 1 May and, last of all, another part of Tomioka on 30 November 2023. That date closed the reopening of the six bases, not of the Difficult-to-Return Zone.

For the rest of the zone the law was amended again in June 2023, creating Specified Living Areas for Returnees, which each town draws around the homes of residents who want to return. Okuma's and Futaba's plans were approved in September 2023, Namie's in January 2024 and Tomioka's in April 2024; Minamisoma and Katsurao have plans as well. Decontamination began on 20 December 2023. On 22 June 2026 Okuma eased entry to part of its areas and opened applications for preparatory overnight stays: 179 households from about 199 ha across five districts, within roughly 570 ha designated. In October 2026 Futaba announced it will lift the order on about 113 ha in two districts in December, the first lifting in any of these areas, and expects to do the same for a third district by the end of March 2027.

So the claim that Fukushima's exclusion zone has been fully reopened does not hold. What ended in November 2023 was the reopening of the reconstruction bases; the Difficult-to-Return Zone is still under an evacuation order. Fukushima Prefecture puts it at around 2.2% of its land area on a page updated in August 2026, and the Reconstruction Agency gives the same share with information as of April 2024. Nor is it a circle: Iitate, outside the 20 km radius, had a Difficult-to-Return Zone, while towns inside the radius reopened years ago. What sets the border is measured dose and the progress of decontamination.