DERBY LINE, VERMONT/STANSTEAD, QUEBEC (Reuters) - During the six-hour drive from New York City to a tiny town in northern Vermont, Iranian student Shirin Estahbanati cried at the thought of seeing her father for the first time in nearly three years. Since then, he had suffered a heart attack, and she hadn't dared leave America to comfort him.

But as she traveled north, she also couldn't stop worrying. What if she missed the turnoff and drove across the U.S.-Canadian border by mistake?

Estahbanati, like many Iranian students in the United States, has a single-entry visa and can't leave the country without risking that she won't be allowed back in. And her parents, as Iranian citizens, are blocked by U.S. President Donald Trump's travel ban from visiting her in the United States.

She didn't want to miss her destination: the Haskell Free Library and Opera House.

Estahbanati and her family had agreed to meet around 9 a.m. at the library, which through a historic anomaly straddles the U.S.-Canada border - and today has been thrust into an unlikely role as the site of emotional reunions between people separated by the administration's immigration policies.

The 31-year-old parked her car and, excitement battling with anxiety, walked to the entrance of the Victorian building. But two hours later, her parents and sister still had not appeared from the Canadian side, and her calls to her sister's cell phone went unanswered.

Finally, she saw them. Because of construction near the library, their GPS device had sent them to the line for the U.S. port of entry. Her parents had no U.S. visas, and they had been detained by American border agents. After approximately two hours, they were released and allowed to join Estahbanati at the library. [...]

This year, as migrant families from Latin America were separated at the U.S. southern border, a more nuanced reality has been playing out on the northern frontier with Canada. Here, dozens of Iranian families have reunited at the Haskell library. Drawn by word-of-mouth and a smattering of social media posts, they have come to the geopolitical gray zone at the rural frontier library, located at once in Derby Line, Vermont, and Stanstead, Quebec.