Thurber, a senior from Riverside, Conn., was the first Oxy woman to finish, placing 143rd out of 277 runners, with a time of 23:09.1 in the 6K.
"For a senior to finish her career at a national championship is a storybook ending," Oxy head coach Rob Bartlett said. "She's been a positive representative of our program, has improved every year and is a great leader. We're just really proud she got to stand on the start line at a national championship in her last cross country race."
Lim, a junior from Piedmont, wasn't far behind, placing 151st at 23:13.4.
"Kayla got a great experience," Bartlett said. "She's improved a ton this year and now she knows what to expect going into her senior year. It's only going to make her a better runner in the future."
Johns Hopkins won the women's national championship and Parley Hannah of Ithaca was the women's individual winner at 20:53.8.
Scarlett, a sophomore from San Diego, placed 186th out of 280 men's runners, going 25:59.4.
"He's only a sophomore, so the fact that he's already got nationals experience and two years to progress, is great for our entire men's team," Bartlett said. "We have a young team and Matt's leading the way. I expect he'll be coming back and bringing some teammates with him."
Patrick Watson of Stevenson was the overall winner of the men's race, completing the course in 24:13.9, and Pomona-Pitzer won the men's national championship.
The national championship caps a very good year for both Oxy cross country teams. The Oxy women placed third and the men placed fourth at the NCAA Division III West Regionals where each team had all five scorers finish in the top 35, earning All-Region honors.