Leaving Detroit Michigan, heading due south, which foreign country would you reach first?

Because of the way the US-Canadian Border curves around, due south of Detroit is Windsor Ontario. You can drive through the Detroit Windsor Tunnel, and the US-Canadian border is about halfway across the Detroit River.

The Detroit–Windsor Tunnel connects Detroit, Michigan, in the United States, with Windsor, Ontario, in Canada. It is the second busiest crossing between the United States and Canada.

Length: 5,151′ 0″

Toll: USD 4.50/CAD 4.50 {Northbound into the U.S.}

USD 4.75/CAD 4.75 {Southbound into Canada.}

The tunnel opened to regular traffic on November 3, 1930. The first passenger car it carried was a 1929 Studebaker.

In the first nine weeks it was open, nearly 200,000 cars passed through the Detroit-Windsor Tunnel. It's about 9 million cars a year now.