They were a 2.4-mile hike on the lower slopes, a 5.2-mile moderate hike, an 8.4-mile challenging hike and a 13.7 summit hike.
Patch editor David Mills took on the 8.4-mile hike this year and met some hearty and interesting people along the route.
First was Andy, a Concord native who graduated from Mt. Diablo High School and moved back to Concord after living in Benicia for awhile.
Andy's wife works with Shelter Inc. and he was hiking for the second straight year. He said he was happy to walk some hills to support such a worthy program.
A little farther up the trail was Molly, a San Ramon Valley High alum who graduated from the University of Oregon this year with a degree in environmental science.
She was joined by her boyfriend Stevie, an Amador Valley High alum who also graduated from the University of Oregon and works in the high-tech industry.
Walking with the couple was Marina, a neighbor of Molly's family in Danville who rides the trails of Mount Diablo on her mountain bike most weekends.
Another neighbor is a volunteer with Shelter Inc. and convinced them to do the hike.
It was Marina's second Hike for Shelter event. It was a first for Molly and Stevie, neither of whom frequents the trails of Mount Diablo.
All three said there were hiking because it's important to provide shelter for homeless people.
Just ahead of them was Bob and Laurie, a husband-and-wife team from Danville. This was their second year doing the hike.
Like the others, they felt it was important to support Shelter Inc. Plus, they love the trails of Mount Diablo.
At the top of Staircase Trail just off the Wall Point Trail, the group caught up with the Lafayette Ladies, as the contingent was known among the hikers.
This group of 11 women from Lafayette raised more than $4,000 with their hike.
They were organized by Stephanie, who did the 5-mile hike last year and was so inspired she convinced 10 of her friends to join her on the longer hike this year.
Some of her friends got well acquainted on the route.
They became quick friends with Bob, Laurie, Marina, Molly and Stevie, especially when Marina turned over a cell phone she found on the lower trails that belonged to one of Lafayette Ladies.
The larger group hung together as they turned the corner up higher on Summit Trail and headed down the Barbecue Terrace path.
Ahead of them were Brooks and Larry, two friends in the real estate business who had started out on the route early.
The two Lafayette residents do work for Shelter Inc. and thought it would be good business to do the hike.
They quickly found the inspiration the others experienced on the adventure.
"I think we're hooked. We'll be doing this every year," said Brooks.
Brooks' bad knee started to lock up on him on the downward trek through the valley, so they were moving slowly. He and Larry were eventually passed up by the other group, but Brooks was happy to have his photo taken by Patch as proof he was on the trails.
"It'll show my wife I was really out here and not eating breakfast at Millie's," he said.
Bob, Laurie, Marina, Molly and Stevie formed a smaller group and moved ahead of the others.
They finished the hike in 2 hours, 40 minutes and were greeted by volunteers. The rest of the group arrived shortly afterward.
Everyone took the shuttle buses back to the staging area at Monte Vista High, where the adventure had begun a few hours before.