The St. Agnes Convent and School is a mid-nineteenth century educational and religious complex that also includes a historic rectory and a barn. The convent was home to Father Caspar Rehrl and the Sisters of St. Agnes, the religious order Rehrl founded. By the mid-1840s, Catholicism in Wisconsin was predominantly German with its nucleus in the southeastern portion of the state. Father Rehrl was among the first to minister to this new and ever increasing population of people. As one of the pioneer Catholic priests, Father Rehrl was instrumental in the development of Catholicism in East-Central Wisconsin through his extensive missionary work and establishment of numerous churches throughout the area. Beginning in 1858, Father Rehrl was able to serve the region by establishing the convent and school in Barton. At the convent school, children, regardless of ethnicity, religion, or physical ability, found refuge and an education. Though the Sisters of St. Agnes left in 1870 to establish a new motherhouse, Father Rehrl remained at the convent, conducting sermons, teaching, and publishing for the remaining years of his life. Father Rehrl died in 1881.

Father Rehrl’s mission and educational philosophies extended to other communities where he helped built churches and installed teachers. He built a number of churches and preached over a very large area. At least 32 congregations are linked to Fr. Rehrl, either in their founding or as recipients of his service. In addition to founding parishes, Father Rehrl played an important role in the early history of education. His impact on area education was two-fold: the children of the area, regardless of religious background, received a broad education and the sisters of the convent, the pool of instructors from which he staffed schools, were trained, taught the subject matter, as well as the art of teaching it. The order founded by Father Rehrl, the Sisters of St. Agnes, was in charge of at least 23 schools in 1870, stretching from the southeastern part of Wisconsin to the Fox River Valley. It was also in this year that they opened their first out of state school in Ohio. The Sisters of St. Agnes continue to regard Reverend Caspar Rehrl as their founder and the old stone convent as their origin.

The Washington County Historical Society operates the complex as a historic site.