Which officials are typically elected to serve at the county level?

County commissioners are typically elected officials responsible for governing and overseeing county operations and services. They are crucial participants in local government, making decisions on matters such as budgets, land use, and public services. Their role is important as they directly impact the administration of local policies and the management of resources within the county.

Federal representatives are elected to serve at the national level in Congress, and state legislators serve in state legislatures, focusing on state governance rather than county issues. Mayors, although elected officials, serve at the city or municipal level rather than at the more localized county level. The position of county commissioner encapsulates the responsibilities and governance at the county tier, making it the correct answer in this context.