Slate’s new history vault published a gem from the Cold War last week. This map from January 1955 shows the areas in the United States that Soviet citizens could not travel.

This map shows where Soviet citizens, who were required to have a detailed itinerary approved before obtaining a visa, could and could not go during their time in the United States. Most ports, coastlines, and weapons facilities were off-limits, as were industrial centers and several cities in the Jim Crow South.

These restrictions mirrored Soviet constraints on American travel to the USSR. Both the United States and the Soviet Union had closely controlled the movement of all foreign visitors since World War II. A 1952 law in the U.S. barred the admission of all Communists, and therefore of Soviet citizens. (An exception was made for government officials.)

The Soviets’ decision to relax their controls after Joseph Stalin’s death in March 1953 left the U.S. open to charges that it, not the USSR, was operating behind an Iron Curtain. President Eisenhower and his foreign policy advisers decided to mimic Soviet policy as closely as possible: As of early 1955, citizens of either nation could enter approximately 70 percent of the other’s territory, including 70 percent of cities with populations greater than 100,000.

As a North Dakota native, my first question was why prohibit travel to all of western North Dakota and most of South Dakota? (hint: it’s probably not what you think…)

My initial thought was that restrictions were in place in the region because the area is home to two SAC bases — Ellsworth Air Force Base outside of Rapid City in western South Dakota and the Minot Air Force Base in north central North Dakota. The area was also littered with ICBM silos. As a kid, I remember the daily training runs of the B-52s overhead and perhaps the restricted area included the training flight paths.

But this explanation doesn’t seem to fit. First, the airbases did not take on the B-52s until the late 1950s and the ICBMs were not deployed until the early 1960s. True, but weren’t the plans in place in 1955 to deploy both B-52s and ICBMs to the region — so maybe the restrictions were anticipatory? Yes, but then why doesn’t the map include restrictions on access to north eastern North Dakota near Grand Forks (another SAC base) and Devils Lake — one of the largest ICBM fields? And why doesn’t it restrict access to south-eastern Wyoming and western Nebraska near Warren AFB? Hmmm.

Since several cities in the Jim Crow south were off limits, it seems more likely that the travel ban on the Dakotas was motivated by similar concerns — the area is home to several Native American reservations: Fort Berthold, Standing Rock, Cheyenne River, Pine Ridge, Crow Creek, Rosebud, and Yankton. The timing of the map in 1955 corresponded with the U.S. government’s highly contested termination policy which intended to grant Native Americans rights of American citizenship but end tribal sovereignty and tax exemption and close the Indian reservations and sell off property and resources. At the time, the Soviets were countering criticism of their human rights records by proclaiming their support for African Americans and Native Americans. The Native American reservations were seen by conservative backers of the termination policy as a form of socialism and communism and there were plenty of hyped up fears that the Soviets would exploit and facilitate Native American resistance to the termination policy and foment anti-government agitation.

This is all a bit speculative. I’m curious if anyone has further insights.