To assist Contra Costa County in its commitment to Equal Employment Opportunity, applicants are asked to voluntarily provide the following information. Contra Costa County only accepts online applications.When viewing a job posting for a currently open examination, you can select the option that says 'Apply'. Learn why you must write a job acceptance letter and how to write one with a professional touch through our tips and free samples. You can sign up for Job Interest Cards through the organization's web site so that you are notified when jobs become available.