St. Mark's history in Portland goes back to 1891, just before the coming of the railroad to the prosperous river port town. Episcopal Bishop Daniel Sylvester Tuttle sent two lay members from Trinity Church in St. Louis to found a school for boys, away from the "corrupt influences" of the city.
James Harry Gill and F. E. Alleyne, principal and assistant of the new boarding school, chose a bluff high above the Missouri River less than a mile west of Portland as the site and established a 175-acre campus with a chapel, classrooms, and two dormitories for an enrollment of some 55 boys, ages 10-14, the faculty, and a housemother.
Despite early success, the school closed in 1895 and the majority of the school's structure was razed. In 1909 the Archdeacon of the Diocese acquired a tract of land and raised money to build the present St. Mark's Church. St. Mark's was one of four identical churches built in the Diocese of Missouri in the early 1900s. The other three stone churches were in Fulton, Bonne Terre, and Salem. (St. Mark's is the only church of the four still used today.) St. Mark's Church was officially founded in April of 1910.
Until lay leaders were licensed to hold services, a priest came from Grace Episcopal Church in Jefferson City once a month to lead services. The congregation began a long history of strong lay leadership that continues today.
On July 24, 1994, Bishop Hays Rockwell came to St. Mark's to dedicate a new multi-purpose parish hall and rededicate the refurbished sanctuary. With diocesan support, the congregation raised funds to construct the 600-square foot parish hall with contemporary building materials compatible with the stone of the church. Besides offering space for activities for both the parish and the community, the new structure doubled the size of the church facilities and included the first indoor plumbing available to the congregation.
It may be fair to say that Portland's most active institution today is St. Mark's Episcopal Church. It is one of only two churches in the town (the other is a Baptist church). The dedicated members of St. Mark's are responsible for many of Portland's community events. In 2021 Bishop Deon Johnson honored the congregation of St. Mark's with a Bishop's Medal for their outstanding ministry in their community.
In 2022 the Rev. Jessica Wachter became the Vicar of St. Mark's, continuing to encourage and support this small group of good and faithful servants.