The Contra Costa Mosquito & Vector Control District is dedicated to the health and welfare of the county's more than 1 million residents covering 736 square miles. The District has been protecting public health since 1927 when residents formed the District. Funded through tax dollars, the District offers free services for mosquitoes, rats and mice, ground-nesting yellowjackets, ticks, and skunks. Its trained and certified employees work daily to reduce the risk of diseases spread by insects and animals by controlling them in a responsible, environmentally-conscious manner.