SPRINGFIELD — The U.S. Census Bureau announced Monday Illinois will lose a seat in Congress based on the results of the 2020 census.Illinois will move from 18 to 17 seats in the U.S. House, an expected result after some advocates had warned that an undercount could lead to the loss of two seats. The state has lost at least one congressional representative in eight of the last nine decades after peaking at 27 seats in 1910 and remaining there until the 1940 census.Six other states will also lose a seat, including California …