
Grandpa changed his name to "John Marius Jensen" when he immigrated to America.
Helen says he first settled in Minnesota, worked on a farm, and took night classes to learn English. He moved to New York before long. Dad has no recollection of Grandpa landing in Minnesota. Dad says that Grandpa recounted seeing Buffalo Bill Cody's Wild West show, with such spectacles as Sitting Bull.
Besides working as a milkman, Grandpa also worked in a powder (explosives) factory (where he was once knocked unconscious in a blast). He also drove a trolley car. He worked mostly as a farm worker and a gardener. He went to look for farm work at the "Farmer's Union" (or something similar), which may have been out on Long Island.
The 1920 Census shows a John Jensen living on Old Field Road in Brookhaven, NY. There is such a road that leads into a village called Old Field in Brookhaven (Dawn tells me that Brookhaven's boundaries are quite extensive). Dad says that Grandpa talked about how he used to fish for flounder at Old Field, so the John Jensen in the census may have been Grandpa. Dawn has stopped by to see this residence, which she says seems like a place where Grandpa might have lived and worked.
Dad recollected this fishing story after I mentioned Old Field; he didn't mention Old Field previously. On a later occasion, Dad mentioned Farmington, but the only Farmington I could find is far upstate. There is a Farmingdale on Long Island.
That 1920 census record states that Grandpa immigrated in 1915. This conflicts with the date Grandma gave me, 1911. It also conflicts with Dad's recollection that Grandpa once saw Buffalo Bill's Wild West Show, which ended in 1913, if I recall accurately.
Dad says that Grandpa used to go fishing at Old Field, which is a town on the North shore of Long Island. The 1920 Census lists a John Jensen in Old Field.

Grandpa probably met Grandma in 1922. He was a milk man and she was a waitress at the time. They probably married in Spring, 1923. They lived in Manhattan. Their firstborn, Helen, was born September 20, 1923. Helen says she was born in Willimantic, NY. I haven't been able to find any record of this town. She also says she was born on Grandpa's dairy farm (near Oneonta, NY). Dad was born nearly a year later in a hospital in Oneonta.
The dairy farm near Oneonta was the only home Grandpa ever owned, and the first home of Helen and Dad. Perhaps around the time Dad turned two, the farm was destroyed in a fire.
The family moved back to New York City, Grandpa went back to being a milkman, driving a horse-drawn buggy, and Grandma managed the apartments they lived in. Helen says they lived in Greenwich Village.
Besides working as a milkman, Grandpa had also worked in a powder (explosives) factory (where he was once knocked unconscious in a blast). He also drove a trolley car. He worked mostly as a farm worker and a gardener. He would look for farm work at the "Farmer's Union" (or something similar), which may have been out on Long Island.
Grandpa suffered from diabetes from the time Dad was very young (about 3), himself suffering from diphtheria. The diabetes first struck hard after they returned to Manhattan (1927? age 36?). Grandpa was eventually crippled and blinded by the disease, but he lived to age 82.

Grandpa had a friend named Johannes Jepson, who may have known a Peter Jensen in New York. Duska, Al, and Trish all knew and old man named "Jepson" who would come for visits bearing coins for them.
Aunt Helen remembers an Uncle Peter who would give the two kids silver dollars, and that this "uncle" turned out to be their grandfather. Dad is equally certain that they didn't call this "uncle" by that name, but that there was a Peter Jensen was only a friend of the family. Peter Jensen could have possibly been Grandpa's uncle Peder, whom I didn't find in Hornslet in 1890, but again Dad doesn't think so.