Jeff hikes 1/2 mile every 15 minutes. How far does he hike in a 1 hour

To find the distance Jeff hikes in 1 hour, we need to determine how many times 15 minutes goes into 1 hour.

Since there are 60 minutes in 1 hour, and Jeff hikes 1/2 mile every 15 minutes, he hikes 1/2 mile x (60 minutes / 15 minutes) = 1/2 mile x 4 = 2 miles in 1 hour. Answer: \boxed{2}.