In this report, we first provide information on what the Census is. Second, we discuss how the Census is conducted—including the steps the federal government has taken to date and what it plans to do over the next few years to conduct the 2020 Census. (We also describe state efforts to supplement these federal activities.) We then discuss the likelihood of an undercount in California in 2020. Finally, we discuss the implications of an undercount for California both in terms of representation in Congress and federal funding.