Bernice is a town in Union Parish, Louisiana, United States. The population was 1,689 at the 2010 census, a decrease from 1,809 in 2…Bernice is a town in Union Parish, Louisiana, United States. The population was 1,689 at the 2010 census, a decrease from 1,809 in 2000. It is part of the Monroe Metropolitan Statistical Area. The area was part of the Louisiana frontier and pine forests, but early houses survive from the mid-nineteenth century: among the oldest homes are the R.T. Moore/Gresham/Stenzel House, known as the "Sweet Onion", and McCuller Log Cabin, both circa 1865.