Once again, the USA Track and Field Cross Country U.S. Nationals was held on the Flatirons Golf Club grounds in Boulder, Colorado. On Saturday, Chris Derrick of Portland, Oregon and Laura Thweatt of Superior, Colorado won the Open Men 12k and Open Women 8k races under sunny skies and unusually warm temperatures.

One of the perks of the races – the top 6 in Open and Junior categories qualified for the 2015 IAAF World Cross Country Championship March 28 in Guiyang, China.

In addition to the Open, Junior and Masters national championship races, the meet also featured High School Challenge races for boys and girls.

All photographs © Timothy Carlson

Brianne Nelson of Golden, Colorado (677) and Laura Thweatt of Superior, Colorado (703) take early lead in Open Women 8k. Thweatt won in 27:42.

Knox Robinson of Beacon, New York placed 43rd in Masters Men 8k in 30:23.

Craig Greenslit of Berthoud, Colorado placed 16th in Masters Men 8k in a time of 28:19.

Jacques Sallberg of Pasadena, California won Masters Men 8k in a time of 26:29.

Girls High School Challenge start.

Eleven-year-old competitor placed in top the 10 of Girls High School Challenge.

Girls High School Challenge finisher.

Friends holding hands at finish of Girls High School Challenge.

Competitors in Boys High School Challenge.

Katie Rainsberger of Colorado Springs, Colorado (534) leads early in Junior Women 6k. She finished 3rd in 22:11.

Kaitlyn Benner of CU Boulder won the Junior Women 6k in a time of 21:48.

Mary Grace Doggett of North Carolina State recovers after finishing 8th in Junior Women 6k in a time of 22:47.

Friends congratulate Eric Hamer of Monument, Colorado after finishing 4th in the Junior Men 8k in a time of 25:49.

Brie Felnagle of Tacoma, Washington finished 4th in Open Women 8k in a time of 28:23.

Jennifer Rhines of Boston, Massachusetts (687) finished 3rd in the Open Woman 8k in a time of 28:21.

Competitors in Open Women 8k hug after the race.

Augustus Maiyo of Colorado Springs, Colorado (791) leads early in Open Men 12k. Maiyo finished 9th in a time of 37:29.

Adriano Joe of Pinon, New Mexico (574) takes early lead in Junior Men 8k. Joe finished 26th in 27:47.

Chris Derrick of Portland, Oregon (753) leads early in the Open Men 12k.

Chris Derrick drinks some water after winning his 3rd straight USATF Cross Country National Championship in a time of 36:18.