The line at Derby Line VT / Stanstead, QC outside the Haskell Free Library and Opera House. Right in the middle of town. (A few miles away, there is CANUSA street ... houses on one side in the US, other in Canada). In one instance I drove into Canada, crossed the street, cleared customs, then crossed to the other side of the street again to drive eastward, technically in the US for a bit before re-entering Canada.