Indiana Code Title 36. Local Government § 36-7-5.1-8

Sec. 8. (a) A commission may adopt a comprehensive plan (as provided for under the 500 Series of the advisory planning law) for the development of the joint district.  The comprehensive plan, if adopted, does not have extraterritorial effect outside the defined boundaries of the joint district.  However, a comprehensive plan adopted by a commission supersedes an existing or conflicting comprehensive plan governing any of the joint district.

(b) Before exercising its rights, powers, and duties under this chapter or the advisory planning law with respect to an area designated as a joint district, a commission must file with the recorder of each county in which a part of the joint district is located a description or map defining the limits of the joint district.  If the commission revises the limits, it shall file a revised description or map defining those revised limits with each recorder.

(c) Until the commission adopts a comprehensive plan, a comprehensive plan that was in effect before the formation of the joint district applies to that portion of the joint district controlled by that comprehensive plan.

(d) Whenever a new municipality is incorporated and its boundaries lie in whole or in part within a joint district, the commission continues to exercise territorial jurisdiction within the new municipality or that portion of the municipality within the joint district, until the effective date of a municipal ordinance:

Beginning on that effective date, the planning and zoning function of the municipality shall be exercised by the municipality under the advisory planning law or area planning law.