To determine Magan's walking rate in miles per hour, we can use the formula for rate:
\[ \text{Rate} = \frac{\text{Distance}}{\text{Time}} \]
Here, the distance is 12 miles and the time is 6 hours.
\[ \text{Rate} = \frac{12 \text{ miles}}{6 \text{ hours}} = 2 \text{ miles per hour} \]
So Magan's walking rate is 2 miles per hour.