They're the only group attending from the state of California. Fourteen horses are being transported across the country and they'll be on the road for 53 straight hours.
It's not the first time for some of these posse members who attended the inauguration of George W. Bush.
"I hope the weather is good," Capt. Leroy Vierra with the MCSO said. "The last time I went it was freezing cold, 12 years ago, I hope this time we have pleasant weather and everything happens safely and we come back good."
Vierra says they applied to attend the inaugural parade last May and decided no matter who won the election they would attend the event.
Before they left Merced for their long road trip, a priest blessed the horses and led the posse members in prayer.