The students opted out, with either their parent's permission or if they were over 18 years old, decided on their own.
"That's outstanding," said Mancos School District Superintendent Brian Hanson. "I will be honest with you, they are not alone."
And the Mancos School District is not alone, students across Colorado are opting out of the state-mandated Colorado Measures of Academic Success, Science and Social Studies test, referred to as CMAS.
"Our kids have finally decided that enough is enough," Hanson said.
Parents of hundreds of high school seniors in Boulder County, Douglas County, Montrose County and elsewhere are pulling their children out of new state science and social studies tests this month in an escalating battle over Colorado's battery of standardized tests.
The parental refusals - or "opt outs" - are concentrated in a few of the states's highest-performing and most affluent school districts.
At nine Douglas County high schools, nearly 1,900 seniors - or half - didn't take the tests, according to preliminary data from the district.
In the Boulder Valley School District, officials projected at least 1,200 refusals at three high schools.
In Mancos, all 17 of the high school seniors opted out.
Hanson said the students have had a far reach in social media and elsewhere. In fact, the students have been asked to present at the Colorado Association of School Board's conference early next month.
Hanson emphasized that students aren't against teachers' tests, just the state's standardized tests.
"It is the standardized testing movement that has got out of control," Hanson said. "There has got to be a better way to do it."
"We've reached the breaking point," he added. "People don't want to teach any more. We are pushing back."
Taryn Gordanier, a junior at the Mancos High School, is taking part in a local campaign to end the testing.
"Testing is a loss to valuable instructional time," she said. "We feel these tests are put before our education, and we are not No. 2 - we are No.1."
To demonstrate this, the group of kids recently posted a photograph on their social medial site of them breaking No. 2 pencils in protest.
"We are trying to make it known that our education is No. 1, and these tests are making us No. 2, just like the pencils used to take them," Gordanier said.
Others feel the tests are too stressful.
"I feel like they put so much pressure on the student, and at the same time there are a lot of questions on there that we don't know because we spent more time on something else," said Jessica Gutierrez. "Some students don't test well either."
Annalisa Mykytiuk, a junior at Mancos High School, said their social media page has had over 400 likes and is growing.
"There are better options," she said.
Students at Fairview High School in Boulder protested Thursday morning on school grounds and a median, while others gathered in the gym to make signs and write letters to legislators, at a time they were supposed to be tested on their mastery of standards in the subjects.
"We have grown up taking standardized testing - since third grade," said senior Jessica Piper. "This particular protest comes as a result of this frustration taking these tests we don't feel are adequate."
Districts and schools face consequences if their participation on state-mandated tests dips below 95 percent. For districts, it could mean a lowering of their accreditation level and other sanctions, and for schools it eventually may mean adopting more stringent plans requiring additional steps to meet state requirements.
Students who skip the tests do not face consequences if their parents go through the proper channels and absences are excused.
In a statement Thursday, Colorado Education Commissioner Robert Hammond said he hears the concerns.
"I understand the frustration," Hammond said. "I am fully committed to evaluating how the testing goes and working with districts and policymakers to identify ways to improve. I know that together we will find the best pathway forward that yields the best results for students."
A task force created by state legislators has been meeting to discuss state assessments and is to issue recommendations in January. The issue then will be in the hands of the General Assembly.
The standards and tests in science and social studies were developed in Colorado, and are not part of politically divisive Common Core standards in math and language arts the state adopted.
Concerns about a poor showing might also be a factor in the protests. In tests given last spring, Colorado elementary school students scored dismally in the new science and social studies tests.
Only 17 percent of Colorado fourth- and seventh-graders scored "strong" or "distinguished" in the first social studies tests. That means those students are on track to be ready for college and a career.
Large numbers of refusals also were expected in Cherry Creek School District.
The Associated Press contributed to this report.