From the North:
Take I-55 south
Take the Stevenson Drive/East Lake Drive Exit (#94)
Turn left onto Stevenson Drive, which changes into East Lake Drive once you cross over the dam
Follow East Lake Drive for approximately 4.5 miles
There will be a sign for the zoo, turn right here and you will come the the zoo's parking lot

From the South:
Take I-55 North
Take the Chatham/East Lake Drive exit
Turn right and follow this road until you come to a fork in the road at Cottonhill Park
Veer to the left
At the stop sign, continue traveling to the left
Follow East Lake Drive for approximately 5 miles
You will see a brown sign for the zoo
Turn left onto Long Bay Drive
At the stop sign, turn right and you will see the zoo parking lot