Marianne H. Otto, of Sioux Falls, South Dakota, passed away on Tuesday, October 27, 2026, at Edgewood Senior Living in Sioux Falls. She was 86 years old.

Marianne Helen McNamara was born on November 7, 1939, in Marshall, Minnesota, to Donald and Maxine (Elgie) McNamara. Her family later moved to Sioux Falls, where she graduated from Washington High School in 1957.

On September 29, 1961, Marianne married Albert Martin Otto in Sioux Falls. Together, they made their home there and raised three sons.

Marianne worked as a receptionist at Orthopedic Institute in Sioux Falls. After 23 years in healthcare, she retired.

Faith and family were at the heart of Marianne’s life. She was a longtime member of First Presbyterian Church and celebrated 50 years of membership. Those who knew her will remember her as friendly, sociable, and caring. Marianne was also a member of Beta Sigma Phi Sorority in Sioux Falls, an international, non-collegiate women’s social, cultural, and community-service sorority for seniors. She looked forward to gathering each month with her sorority sisters to take part in community civic activities. The Beta Sigma Phi Senior Sorority is the longest-running and last chapter of the Xi Psi chapter in Sioux Falls. Marianne found many of her closest friends through the sorority and treasured their coffee and lunch outings.

Marianne’s sons, Jon Otto of Sioux Falls and Kent (Kori) Otto of Rapid City, South Dakota, brought great joy to her life, as did her six cherished grandchildren and one great-grandchild. She is also survived by her brothers, Dave McNamara of Sioux Falls and Dick McNamara of Fargo, North Dakota, and her sisters, Donna Helgerson of Grand Forks, North Dakota, and Barb Holstenson of Sioux Falls.

Marianne was preceded in death by her parents, Donald and Maxine McNamara; her former husband, Albert Martin Otto; and her great-granddaughter, Angelina Cortez.

A funeral service will be held at 10:00 AM on Monday, November 2, 2026, at First Presbyterian Church, 2300 S. West Avenue, Sioux Falls, SD 57105. Family will receive visitors from 2:00 to 4:00 PM on Sunday, November 1, 2026, at Miller Funeral Home – downtown, 507 S. Main Avenue, Sioux Falls, SD 57104. Marianne will be laid to rest at Woodlawn Cemetery in Sioux Falls. Sioux Falls.