The Russell and Oberg families immigrated to the U.S. around the same time: the Russells in 1879 and the Obergs in 1887. Oberg certainly sounds Swedish and in fact, was spelled Åberg in the old country. Russell, however, does not sound Swedish at all.
In 1943 Martin Reinhold Wallentin Russell wrote down the story of the name Russell. Martin lived to the age of 94 and was affectionately known as "Pops" to his family. Pops wrote that his great grandmother, born about 1787, married a man named Hanson who died in early adulthood. The couple had three children including Pops's grandmother, their daughter Martha, who was born 1817. Mrs. Hanson married a second husband, a Mr. Russell, who had served in the English army for a time. This couple had no children, but Martha took the last name Russell.
The Russells kept an inn at Hinby, near Malmo, Sweden. Martha married Andrew Jonsson, and this couple had five children: the oldest, Nels Jonsson, was Pops's father. Now here's the naming wrinkle: Andrew and Martha's five children took possession of the inn, but because the ownership was on record as the Russell family, the children all agreed to change their last names to Russell. Thus Pops's father became Nels J. Russell.
This flexibility with last names was not so unusual in Sweden. Until the 1800s, Swedish last names were usually based on the father's first name. For example, Agnes's Oberg ancestors include Lars Jansson (1769-?), so named because his father's first name was Jan. Lars's daughter was Christina Larsdotter (1807-1889). The custom changed for the next generation: Christina Larsdotter married Anders Åberg (1811-1868), and their children all kept the father's last name, later Americanized to Oberg.
No one knows the fate of the inn at Hinby, but Nels and his four siblings all immigrated to Chicago around 1879. Pops spoke no English when he arrived in the U.S., and he initially worked lighting lamplights in Chicago, a job commonly done by immigrants because it required no English. He became the treasurer for the American School and Technical Society in Chicago in 1900, a job he held for 40 years.