The Local Area Unemployment Statistics (LAUS) program is a federal-state cooperative effort in which monthly estimates of total employment and unemployment are prepared for over 7,500 geographic and statistical areas. According to the Bureau of Labor Statistics website, "The concepts and definitions underlying LAUS data come from the Current Population Survey (CPS), the household survey that is the source of the national unemployment rate. State monthly model-based estimates are controlled in "real-time" to sum to national monthly employment and unemployment estimates from the CPS. These models combine current and historical data from the CPS, the Current Employment Statistics (CES) survey, and state unemployment insurance (UI) systems."
The civilian labor force, or just labor force, includes all people age 16 and older who are classified as either employed or unemployed. These are people that are either working or actively looking for work. Those that are active duty military personnel or institutionalized are not included in the civilian labor force (BLS definitions). The unemployment rate is the ratio of the unemployed population to the labor force.