As TSP, Inc. marks its 90th year we look back on a rich history designing legacy buildings that have changed communities in South Dakota, Minnesota, Iowa, Nebraska, Wyoming, and other states.

We have designed the schools our children attend, the churches where we worship, the government centers where officials work to improve our lives, and health and wellness facilities where we heal and stay well.

The best news of all: TSP will continue that path long into the future. We’re involved in multiple projects now, and we know our teamwork across multiple offices and multiple disciplines, our strong sense of service to our clients, and our passion for the work we do will keep us busy in the years to come. We have worked for you for 90 years, and we intend to continue to do so.

Thank you to everyone who has been a part of TSP’s first nine decades. Thank you for helping us build a solid base for a dynamic future.


TSP Holly wood Theatre

Hollywood Theatre | Sioux Falls, SD

1930: Architect Harold Spitznagel opens a one-man firm in Sioux Falls, SD. His first job is remodeling a bakery storefront, and he takes his fee in baked goods. The firm is named, simply, Harold Spitznagel, Architect.

1936: Sioux Falls City Hall, Spitznagel’s first major commission, opens.

1939: The Hollywood Theater, the only movie house Spitznagel will design, opens in Sioux Falls, SD.


1945: A campus plan to expand Augustana College (now Augustana University) was developed. TSP will complete a master plan with SmithGroup in 2020.

1946: Spitznagel family moves into a house he designed at 1209 S. Holly Drive. It is featured in the July issue of Popular Home magazine.

Toller’s Drug Store | Sioux City, IA


Church of St. Mary | Sioux Falls, SD

1950: St. Mary’s Catholic School opens to students. It is followed by the gymnasium in 1951 and the Church of St. Mary in 1958.

1952: The first project at South Dakota State University, Harding Hall, opens to students. The most recent project is the American Indian Student Center, which will open in 2020.

1952: David Rosenstein joins the firm as head of the new mechanical engineering department. Thus begins the start of a multi-discipline firm.

1952: The company is renamed Harold Spitznagel & Associates, Architects & Engineers.


1961: The Sioux Falls Arena opens and becomes South Dakota’s largest such structure, surpassing the Huron Arena, which also was designed by the Spitznagel firm.

1966: St. Philip’s Lutheran Church features a 56 by 32-foot baldachin suspended over the chancel area. Palmer Edie was commissioned to create the baldachin.

1967: Firm name changes to The Spitznagel Partners, Inc., abbreviated as TSP.

1969: TSP opens an office in Rochester, MN.

The Baldachin at St. Philip's

The Baldachin at St. Philip’s Lutheran Church | Fridley, MN


Rushmore Civic Center | Rapid City, SD

1971: Earth Resources Observation Systems (EROS) Data Center opens near Garretson. A new building also was completed in 1996.

1972: Harold Spitznagel retires.

1973: TSP opens an office in Rapid City, SD.

1975: Harold Spitznagel dies at the age of 78.

1976: TSP Wyoming started.


1983: The Minneapolis branch office officially begins.

1984: Ron Mielke becomes president of TSP Group, Inc. His background is in mechanical engineering

Black Hills Regional Eye Institute | Rapid City, SD


IBP World Headquarters – Now Tyson Foods | Dakota Dunes, SD

1994: TSP acquires Weber, Pollard, Schulze, Inc. and begins a Marshalltown, IA presence.

1994: EOS Architecture in Minnetonka, MN merges with TSP, Inc.


2000: LMcArchitects, founded in 1986 in Omaha, NE, merges with TSP.

2002: Mechanical engineer Dick Gustaf is named Chief Executive Officer.

2005: All locations and corporate name changed to TSP, Inc., unifying processes and financials as a single company.

TSP North Education Center

Intermediate District 287 North Education Center | New Hope, MN


Mayo Civic Center Expansion | Rochester, MN

2010: The Department of Architecture at South Dakota State University begins its first year of instruction. TSP is one of four firms to start the program.

2015: Architect Jared Nesje named Chief Executive Officer, the fifth in the firm’s history.

2017: TSP opens an office in Watertown, SD.

2020 and Beyond

Team TSP 2019