Complex sentence: The community was named for a homesteader, Nathaniel Winfield Lowman, from Polk County, Iowa, who settled there in 1907; when he founded a post office four years later, it was named for him.
Split into simpler sentences: The community was named for a homesteader, Nathaniel Winfield Lowman, from Polk County, Iowa. He settled here in 1907, and when he started a post office four years later, it was named for him.