From Utah.com:
An easy albeit steep trail runs from the east side of Provo up to the block Y on the mountain. It is a very popular hike for college students and families. From the Y you get great views of the Provo area and Utah Lake.

The Y is made of concrete that is whitewashed regularly. A nearby generator is used to light it up during special BYU activities. The block letter is 380 feet high and 180 feet wide, and is said to be the largest collegiate symbol in the United States.

The trail to the Y is well-marked and easy to hike.

(Photo taken from the Y)