A rural county library district can be formed to serve the unincorporated parts of a county.  In order to form such a district, at least 10 percent of the registered voters living in the unincorporated areas of a county that voted in the last general election must sign a petition with the county legislative authority.  Once a petition is received, the county legislative authority must put the proposition to voters at the next general or special election.  If a majority votes in favor of the formation of the district, then it is established.

Island library districts can be formed in the same way as a rural county library district, except that an island library district may include the unincorporated areas of a single island only, and may only be formed in counties that are composed entirely of islands and that have fewer than 25,000 people.  An island library district may not be formed if the same area is served by a rural county library district. 

Instead of forming a single-county rural library district, counties can jointly operate intercounty rural library districts.  These districts can be formed in one of two ways.  First, the counties that wish to create the district can adopt identical resolutions to that effect, or each separately be petitioned by 10 percent of the registered voters living in unincorporated areas within each county, and then have the creation of the district approved at the next general or special election by a majority of the voters in unincorporated areas within each county.  Alternatively, a joint session of county commissioners of the counties that wish to be involved in the intercounty rural library district can jointly vote to establish the district. 

Whether a rural county library district or an island library district has been created, the county legislative authority must appoint a board of library trustees to oversee the operation of the library district.  In noncharter counties, or counties with fewer than one million residents, or for island library district, the board consists of five trustees.  For rural county library districts in charter counties with more than one million residents, the board has seven trustees.  These trustees must represent the geographic diversity of the district.  In intercounty rural library districts, the county commissioners of the counties involved jointly appoint a board of trustees of either five or seven.

Whether the board consists of five or seven trustees, the trustees do not receive a salary or other compensation, but their necessary expenses are paid for by district funds.  Trustees serve for five years, but the county legislative authority in a rural county library district or island library district, or joint county legislative authorities in the case of an intercounty rural library district, can remove a trustee for cause prior to the conclusion of their term. 

Despite their names, rural county library districts, island library districts, and intercounty rural library districts can come to include incorporated areas as well as unincorporated areas.  A city or town with fewer than 300,000 people can be annexed to an adjacent library district if the legislative authority of the city petitions for annexation, the local library board or librarian and the district board of trustees concurs, and the annexation is approved by voters within the city during a special election.  A city may later withdraw from the district if at least three years have passed since the annexation and the voters within the city approve the withdrawal at a general election.

Rural county library districts, island library districts, and intercounty rural library districts can be dissolved after three or more years of operation in much the same way as they were formed.  If a petition for dissolution signed by at least 10 percent of the voters within the unincorporated areas of the county or counties is filed with the district's board of trustees at least 90 days prior to a general election, then a petition for the district's dissolution must be placed on the ballot for the election.  If a majority of voters living in the unincorporated areas of the county or counties vote to dissolve the library district, then the district is dissolved.

Voters in cities or towns that have been annexed to a rural county library district, island library district, or intercounty rural district may vote in the election held to determine whether the library district will be dissolved, and these voters are included when determining whether 10 percent of the voters within the library district have petitioned for its dissolution.

If a city or town is annexed into a rural county library district, island library district, or intercounty rural district, the library district's board of trustees must be modified to include representation from the city or town.