State Sen. Tom Wiens (R-Castle Rock) announced Thursday that he will not run for re-election this fall.

"I want to thank you for the opportunity to represent you in the State Senate and I also want you to let you know that I have decided not to seek another four year term in the Colorado Senate," Wiens said in a statement. "I remain committed to working with you to help make Colorado the best possible place to live, work and raise a family. I also know that there are many ways to contribute to the future of Colorado as a private citizen."

With Wiens’ departure, there are no official Republican candidates left in the SD-4 race. Larkspur architect Joseph Alsup is running as a Democrat for the seat.

Wiens, a businessman and rancher, was first elected to the Colorado Senate in 2004 after spending two years as a state representative.