To find the area of a circle, you can use the formula:
\[ A = \pi r^2 \]
where \( A \) is the area and \( r \) is the radius of the circle.
Given that the diameter \( d \) is 2 miles, the radius \( r \) is half of the diameter:
\[ r = \frac{d}{2} = \frac{2 \text{ mi}}{2} = 1 \text{ mi} \]
Now, substitute the radius into the area formula:
\[ A = \pi (1 \text{ mi})^2 \]
\[ A = \pi \cdot 1 \text{ mi}^2 \]
\[ A = \pi \text{ square miles} \]
So the exact answer for the area of the circle in simplest form is:
\[ \pi \text{ Square Miles} \]