1857—Trinity Congregation first organized. Members called Pastor Frederich Boeling from St John’s Pekin to pastor. The first church (a 24x31’ frame structure) was built on rented property at 821 South Adams Street. It also served as the first school.

1858 — A second, larger church (36’X 45’X 18’) was built at a cost of $2,000. This building, was located on the north side of Maple Street near where O’Brien Field stands today. The congregation also wrote its first constitution and became affiliated with what would become the Lutheran Church — Missouri Synod. They constructed an addition to the existing building on Maple Street and used as the living quarters for the pastor. It was described as being "a pretty handsome structure for the times." Also in 1858 with the help of Pastor Boeling, Trinity wrote its first constitution and became affiliated with the Lutheran Church-Missouri Synod.

1872 — A tract of land in Limestone township was purchased for a church and school, and 3 acres were made into a cemetery. The church and school were never built and the entire tract became Lutheran Cemetery. (Today, the cemetery is jointly owned by Trinity and Christ Lutheran Church.)

1875 — A third, larger church was built at the corner of Jefferson and Maple. The congregation later built a parsonage across the street in 1878. This structure would be used for our worship for the next 50 years. The Sanctuary contained a pipe organ that had to be manually pumped (no electricity yet). Membership stood at 800 souls.

1903 — Another school was built at 416-418 Warner St. (what is today the 900 block of SW Jefferson) south of Elm Street. The new 2-story brick school provided two classrooms, an auditorium and several small meeting rooms. One classroom was used for grades 1-4 and the other for grades 5-8. This building served as school and parish hall for the next 36 years.

1919 — The church changed its name from Deutsche Evangelisch Lutherische Dreienigkeits-Gemeinde U.A.C. (German Evangelical Lutheran Trinity Congregation U.A.C.) to Trinity Evangelical Lutheran Congregation U.A.C.

1923 — By the early 1920s, many Trinity members had moved to the "Bluffs" north of downtown Peoria, and the existing church did not fit the needs of a greatly increased membership. So, land was purchased at Hamilton Boulevard and Randolph Street for $15,000. The present church was built there for $135,000. It was designed by prominent architect Frederick Klein, who also designed Peoria Central High School, and the Apollo and Madison theaters.

1925 — Trinity’s current church sanctuary at the corner of Hamilton Boulevard and Randolph Street was dedicated. Membership at the time of dedication was 132 voting members, 600+ communicants and 1250 souls.

1939 — A parish hall/school/gym was constructed at a cost of $85,000. It provided room for two school rooms, a gym and kitchen. The lower level had playrooms for children and meeting space for various groups. Four bowling alley lanes were added later.

1955 — Trinity began a Braille Work Center for the Lutheran Mission with Blind and Visually Impaired Persons.

1956 — Land was purchased in rural Peoria on West Glen Avenue with consideration of starting a new congregation there. The land was designated for Concordia Lutheran School, and in 1959, a new school was built.

1957 — Trinity celebrated its 100th anniversary, dedicating the "Life of Christ" Window at the rear of the Sanctuary in the balcony.

1959 — The congregation built a new office building adjacent to the church.

1969 — Three stained glass windows in the chancel were dedicated. The windows are of a type called Grisaille Windows, referring to the decorative background.

1983 — A new Schlicker pipe organ was installed.

1990 — First full-time Director of Christian Education is hired, Scott Rauch.

1993 — First full-time Cantor (Martin Dicke)  is hired. Our current cantor is Peter Wykert.

1995 — Joined church, parish hall and office building by adding new foyer. Also added air conditioning to the building and made entire campus accessible.

2005 —Pastor Jim Bettermann installed.

2007 — Pastor Mark Nelson is installed.

2012 — Pastor Matthew Synnott is installed.

2017 -- Cantor Peter Wykert added to staff at Trinity.