Crouse was born as Iva Marie Johnson near Nugent, Iowa, on 8 March 1895 as one of six children born to William King and Susie Dorothy (née Lemen) Johnson. After attending elementary school in rural Keokuk County, she completed one year of high school in Sigourney, Iowa.
On 13 September 1914, Crouse married her husband, John Earl Crouse, at the Lancaster Christian Church. The couple settled on a farm near Lancaster, and had two children, Horace and Betty. They moved to Sigourney in 1944. Crouse was a homemaker and typical farmer’s wife, her hobbies including crocheting, reading, and gardening.
Crouse was widowed on 29 October 1977 after 63 years of marriage. She also outlived her parents and all of her siblings, as well as a great-granddaughter.
Crouse died in a Sigourney assisted living facility on 8 March 2006, her 111th birthday. She was survived by her two children, as well as four grandchildren, 10 great-grandchildren, and six great-great-grandchildren.
Crouse’s age was verified by Robert Young and validated by the GRG on 8 March 2005, her 110th birthday.
At the time of her death, Crouse was the second-oldest known Iowa resident, after Hazel Blecha (1894 – 2006).