The Los Angeles County Tobacco Control Program (TCP) is part of the Division of Chronic Disease Prevention and Health Promotion in the Department of Health Services. It was established as a result of the tobacco tax initiative of 1988, Proposition 99/AB75, in December of 1989. The goal of TCP is to establish policies, health services, public education, and media conditions that support the reduction of tobacco use in Los Angeles County and the associated disease, disability, and mortality.

Los Angeles County Immunization Program efforts are targeted primarily toward pediatric and adolescent immunizations , with some adult immunization activities. Although this Program serves the entire County population, many activities are specifically directed toward communities with children at high risk of under-immunization. The Immunization Program partners with other organizations to provide outreach and immunization services in pockets of need areas , which are defined as those areas with large numbers of un-immunized and under-immunized children.

The Scientific Services Bureau operates one of the largest full-service crime laboratories in the United States. A staff of 198 members provides forensic science support to all Los Angeles County law enforcement agencies, except the Los Angeles Police Department. Approximately one half of the nearly 70,000 cases submitted annually to the Crime Lab is from Sheriff's Department investigators , while the remainder is from local, state, and federal agencies. Since 1989 the Scientific Services Bureau has been an accredited laboratory through the American Society of Crime Laboratory Directors/Laboratory Accreditation Board (ASCLD/LAB).

The Republican Party, also commonly called the GOP (for "Grand Old Party"), is one of the two major contemporary political parties in the United States, the other being the Democratic Party. Founded by anti-slavery activists in 1854, it dominated politics nationally for most of the period from 1860 to 1932. There have been 18 Republican presidents, the first being Abraham Lincoln, serving from 1861 to 1865, and the most recent being Donald Trump who began serving in 2017.

A perennial stream or perennial river is a stream or river (channel) that has continuous flow in parts of its stream bed all year round during years of normal rainfall. "Perennial" streams are contrasted with "intermittent" streams which normally cease flowing for weeks or months each year, and with "ephemeral" channels that flow only for hours or days following rainfall.