Okla. Stat. tit. 19 § 866.2
In any county of the state authorized to avail itself of the provisions of this act and form with a city located therein a cooperative planning commission, such city is hereby empowered to adopt, amend, extend, add to or carry out a comprehensive plan for such city under the authority of existing statutes and laws and in addition is hereby authorized to establish a housing code in accordance with the provisions hereinafter set forth in this act, and it may also perform any additional urban planning which is needed including, but not limited to, surveys, land use studies, urban renewal plans, conservation plans, technical service and other planning work.
Such county is hereby granted authority to establish zoning regulations, a building code and construction codes and a housing code in accordance with the provisions of this act for all the area located within three (3) miles of such municipality or within one-fourth (1/4) mile of any state or federal highway located anywhere in the county, or within one-half (1/2) mile of any water supply or reservoir owned by the municipality, excluding, however, any incorporated area, except as hereinafter provided; and further provided that such county is hereby granted authority to adopt, amend, extend, add to or carry out within the jurisdictional limits as provided by this act, excluding, however, any incorporated area and any unincorporated town which has been platted for more than ten (10) years, except as hereinafter provided, all additional elements of a comprehensive plan including, but not limited to, plans for major streets and highways and other elements of water, rail, air and land transportation plans, public facilities plans, capital improvement programs, uniform regulations for land subdivision and for the improvements located thereon, building line regulations, urban renewal plans and conservation plans. However, the provisions of this section shall not be construed to prohibit a municipality in a metropolitan area planning commission from creating its own separate planning commission to act within the boundary of the municipality. In every county of this state having an upstream terminal port and turnaround where navigation ends, or in any county containing all or any part of a reservoir or reservoirs constructed by the Bureau of Reclamation, the United States Army Corps of Engineers or by the Grand River Dam Authority, such county is hereby granted authority, at the discretion of the board of county commissioners, to establish zoning regulations, a building code and construction codes and a housing code in accordance with the provisions of this act for all or any part of the unincorporated area within the county, and further provided that such county is hereby granted authority to adopt, amend, extend, add to or carry out, throughout the unincorporated area of the county, additional elements of a comprehensive plan including, but not limited to, plans for major streets and highways and other elements of water, rail, air and land transportation plans, public facilities plans, capital improvement programs, uniform regulations for land subdivision and for the improvements located thereon, building line regulations and conservation plans.
Okla. Stat. tit. 19, § 866.2