Theresa Thielen, age 83, of Mahnomen, MN, passed away on Thursday, July 9, 2026, at the Mahnomen Health Center Nursing Home in Mahnomen, MN.

Theresa Mary Ackerman was born on October 20, 1942, in Northwood, ND, to John and Pauline (Hemberger) Ackerman. She was raised on the family farm near Ogema, MN, and graduated from Waubun High School with the Class of 1960. After graduation, Theresa spent a few years traveling and working as a waitress before she was united in marriage to Andrew Thielen on June 29, 1963, in Ogema. Together they made their home on the Thielen family farm, where they raised their large family and built a lifetime of memories despite many challenges, including a devastating house fire in the 1970s. Following Andrew's death in 2003, Theresa continued living on the farm until a tornado destroyed the family home in 2013, after which she moved to Mahnomen, where she shared her home with her life companion, Urban Jirik. She later moved to Mahnomen Senior Living in 2017 and became a resident of the Mahnomen Health Center Nursing Home in 2018.

Theresa was never one to be idle. While raising her nine children, she also worked a variety of jobs throughout the years. In the 1980s, she spent five years as a short-order cook at the Pembina Supper Club before working at Pinehurst Resort, where she cooked and cleaned. She later worked at the Red Apple in the mid-1990s before beginning a career she truly enjoyed as a buffet cook at Shooting Star Casino, where she dedicated more than 25 years.

When she wasn't working, Theresa loved creating things with her hands. She was a talented woodworker who built dollhouses and wooden toys that brought joy to many children. She also made countless baby blankets and decorative pillows that became treasured keepsakes for family and friends. She took great pride in her flower gardens and vegetable gardens, faithfully canning the harvest each year. In her younger years, she enjoyed gathering with neighbors for lively card parties and dancing at local halls. Later in life, she appreciated life's simpler pleasures, including sharing a beer after Saturday evening Mass with her dear friend, Sally Simon.

Theresa's faith was an important part of her life, and she was a devoted member of St. Joseph's Catholic Church. Above all, she cherished her family. Whether spending time together at the lake or hosting large Christmas gatherings, Theresa treasured every opportunity to be surrounded by the people she loved most.

"When God created Theresa (Ackerman) Thielen, He knew it wouldn't be easy.  She had to be soft, but tough.  You can't imagine what our mother could do or endure.

She had to have 180 moveable parts…all replaceable;

Run on black coffee and sandwiches;

Have a lap that disappeared when she stood up;

A kiss that could cure anything from a broken hand to a disappointed love affair;

Three pairs of eyes; one pair that saw through closed doors, another pair in the back of her head that saw what she shouldn't but needed to know, and a third pair that said, "I love you, no matter what."

She had to be able to heal herself when she was sick;

Feed a family of eleven on one pound of hamburger;

Weed endless flower beds and gardens;

Teach her children how to drive;

Wash five loads of laundry a day;

Bottle feed one child while spoon feeding another;

Plan big birthday parties, and still have time to make toys for Christmas.

She had to be able to make her children feel special and loved in their own way, and sometimes be taken for granted.

She had to have tears of joy, sadness, disappointment, pain, loneliness and pride.

To know, without being told, that we're always loved and needed in a very special way."

Theresa is survived by her children: Michael (Nancy) Bovy of Pine City, MN, Bradley John Thielen of North Branch, MN, Rodney "Lee" Thielen (Jose Salas) of San Antonio, TX, Vickie (Keith) Drake of Clear Lake, MN, Ken (Nicole) Thielen of Ulen, MN, Dennis Thielen of Morristown, TN, Laura Gulseth (Mark Wrage) of Twin Valley, MN, Larry (Delphie) Thielen of Pleasant Hill, MO, Curt Thielen (Arnold Tan) of San Diego, CA, and Kelly (Nate) Olson of Bagley, MN; 13 grandchildren: Alex Bovy, Ryan Drake (Justin), Felicia (Jose) Chinas, Jesse Thielen (Ashley), Ashley Thielen, Darrell Gulseth, Adam Gulseth (Kalynn), Andy Thielen, Aaron Thielen, AJay Thielen, Asher Thielen, Nikolas (Caitlyn) Olson, and Taylor Olson (Zach); and cherished companion, Urban Jirik of Mahnomen.

Theresa was preceded in death by her parents; husband, Andrew Thielen; infant son, Brian Benedict; sisters, Jeanette and Darlene; brother, Kenneth; and several brothers and sisters-in-law.

A Mass of Christian Burial will be held at 10:30 a.m. on Thursday, July 16, 2026, at St. Joseph's Catholic Church, Beaulieu, MN. Visitation will be held Wednesday, July 15, 2026, from 5:00 – 7:00 pm with a Prayer Service beginning at 6:30 p.m. at the Anderson Family Funeral Home in Mahnomen, MN. Visitation will continue one hour prior to the service at the church. Burial will be in St. Joseph's Catholic Cemetery.