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TMC Earth Day 5K at Biosphere 2

Sat April 19, 2025 Oracle, AZ 85623 US Directions

2024 5k Route, with course map and, staging area map

The route will be solely on the grounds of the renowned Biosphere 2, using back road and locations not available to the public.  

Terrain: The race starts and ends on grass, but it's mostly pavement, with a brief dirt section ... and, well, it's hilly in some sections...

 

The Start: The event starts on the grass of the Great Lawn, crosses some gravel, then drops down a steep hill before heading up another hill that passes the Biosphere 2 complex.  For 2024, we've flattened this hill, with a flat and smooth section through Biosphere out buildings before a gradual climb to the top of the course. There are a few speedbumps on this opening hill, so please keep an eye out for varied terrain.

Mile One: After the first half-mile or so, you'll continue heading north through the Mesquite Forest.  This is a mostly flat section, then you'll take a sharp right turn and plunging downhill. Off to your left will be the snowcapped Catalinas as you head downhill, then you'll begin a gentle climb back up to the beautiful dirt road section, with the mountains to your left and the Biosphere 2 to your right.

Mile Two: The second mile will be a bit twisty as you go past the historic ranch house, then swing downhill past the stables and onto the flat-ish out-and-back.

Mile Three and the Finish: There will be about a 1/3 of a mile of gentle downhill to the turnaround, then you'll come back heading towards the Biosphere 2. The final stretch will head back up the hill to the finish line in the middle of the Great Lawn.

Chair Athletes: Chair athletes may find this a doable but challenging course, with a couple of steep hills and the dirt road.

Strollers: Strollers are allowed in the race, but please be mindful of the hills and ensure that you are tied to the stroller you're pushing. Please remember sun protection.

Headphones: We request that you do not wear headphones while participating in the event. Enjoy the camaraderies of your fellow athletes, enjoy the scenery, and keep an ear open for rattlesnakes, javelinas, and other participants.

Wildlife: This event takes place in a rural environment adjacent to wilderness, so you may encounter any number of wild animals, including but not limited to rattlesnakes and other snakes, javelina, cattle, deer, wild turkeys, horses bobcats, and more. Please do not try to touch the wildlife. Please do not wear headphones.

Heat and Altitude: The race starts at approximately 3820 feet, so be mindful that you're at a bit of elevation. It looks like race morning may be about 50 degrees at the start, climbing to the mid-70's. Stay hydrated, wear sunscreen and a hat.

Measurements: The route is garmin- and map-my-run correct but not a USATF certified course.

Wanna' know more about the location?  Check out this video from 2011, with scenes from the early construction in the mid-80's.

Please carpool. There will be parking in the Biosphere 2 parking lot, but it would help if participants carpooled to share the drive.

Driving Directions from Central Tucson
From central Tucson, go north to River Road and turn left (heading west)
Continue on River Road and turn right on Oracle Road/AZ Highway 77
Drive north approximately 24 miles on Oracle Road/AZ Highway 77
Turn right on to Biosphere 2 Road at Mile Post 96.5

From Phoenix Sky Harbor International Airport
After leaving the airport, follow the signs to I-10 E
Take I-10 E toward Tucson, to Exit 185 and exit the interstate
Turn left onto Highway 387 and continue past Coolidge until Highway 387 intersects with AZ Highway 79 near Florence
Turn right on to Highway 79 and follow this until Oracle Junction where you turn left onto AZ Highway 77
Drive north approximately 6 miles on AZ Highway 77
Turn right on to Biosphere 2 Road at Mile Post 96.5

 

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