Cedar Catholic Jr.-Sr. High School was first called "Holy Trinity," after the parish that gave it its birth. The school was dedicated on January 3rd, 1901. It officially opened six days later, and had 75 elementary grade students who had gone to the public school before. The grade school was used for teaching in the 1900-1901 school year, and added a class each year, so the first class to graduate was the Class of 1905. As time went on, more students continued to enlarge the class sizes.
Over the years, class sizes grew to the point that a new larger school building was necessary. In 1940, the first plans to create a new school arose because of overcrowding in the old one. It was immediately planned to create the first floor of the building southeast of the church, and then add the second and third floor when the need for them arose. This building is still used today and is the south part of the Jr.-Sr. High School.
By 1956, the increase in enrollment in both grade and high school increased so much, that plans were formed to create another school building for the elementary students. That new elementary school is now Holy Trinity Elementary School, which is southwest of the Jr.-Sr. High School and south of the church. At that time, the building plan consisted of eight rooms, a gymnasium/parish center, a cafeteria, and a well equipped kitchen.
When the year 1963 had come, 10 parishes came together to support the school, which they renamed to “Cedar Catholic High School." Uniforms were then introduced in the 1963-1964 school year. Many of the parents were grateful, because now the students didn’t have to compete with each other when buying clothes. The new uniforms, according to teacher Sister Pierre,” wearing of uniforms also helped with discipline.”
In the year 1995, junior high students from the area schools were moved into the high school. The school name then had to be changed to its present form: Cedar Catholic Jr.-Sr. High School.
In the 2004-2005 school year, Cedar Catholic celebrated its 100th anniversary. The school received letters from the State Governor, The Archdiocese of Omaha, the City of Hartington, and even a letter from Saint Pope John Paul II. Also during that school year, the ground breaking ceremony for the Msgr. Cyril Werner Activity Center happened on November 4th. The building was constructed from 2005 to 2006. Today, the building is thoroughly used for games, activities, concerts, and other events throughout the year.
Today the schools are still being upgraded and modified. Recently, the Jr.-Sr. High school updated their air conditioning and heating units. The classrooms are being equipped with new technology, including smart boards, iPads, and computers to aid in teaching.