Legislative authority of a County is vested in the County Assembly as spelt out in Article 185. The members of the County Assembly may make laws that are necessary for effective performance of the County government as set out in schedule four. The functions of the County Assembly are;

1. To make any laws that are necessary for, or incidental to, the effective performance of the functions and exercise of the powers of the County government;
   While respecting the principle of the separation of powers, to exercise oversight over the County Executive Committee and any other County executive organs; and,
2. To receive and approve plans and policies for the management and exploitation of the County’s resources; and the development and management of its infrastructure and institutions.

No civil or criminal proceedings may be made against a member of the County Assembly for anything said in any debate, petition, motion or other proceedings of the County Assembly.

Membership of the County Assembly

Article 177 of the Constitution lists membership of the County Assembly as follows:

1. Members elected by the registered voters of the wards;
2.  The number of special seat members necessary to ensure that no more than two-thirds of the membership of the Assembly is of the same gender;
3. The six nominated members of marginalised groups, including persons with disabilities and the youth, prescribed by the County Government Act; and,
4. The Speaker, who is an ex officio member.

The County Assembly Service Board

This is provided for in section 12 of the County Governments Act. Each County Assembly shall have a County Assembly Service Board.
The County Assembly Service Board is made up of the Speaker of the County Assembly as the Chair; leader of the majority or a County Assembly Member appointed by him as the Vice Chair; leader of the minority party or a County Assembly Member appointed by him and one person resident in the County who is appointed by the County Assembly from among people who have knowledge and experience in public affairs but who isn’t a member of the County Assembly. The assembly clerk shall be the secretary to the board.
The County Assembly Service Board is responsible for;

1. Providing services and facilities to ensure effective and efficient functioning of the County Assembly
2. Constituting offices in the County Assembly service, appointing and supervising office holders.
3. Preparing annual estimates of expenditure of the County Assembly service and submitting them to the County Assembly for approval and exercising budgetary control over the service.
4. Undertaking, singly or jointly with other organisations programmes to promote ideals of parliamentary democracy
5. Performing other functions necessary for the well being of members and staff of the County Assembly or other functions prescribed by the national legislation.