Ohio constitution
Article X: county and township organizations
Section 3

The people of any county may frame and adopt
or amend a charter as provided in this article but the
right of the initiative and referendum is reserved to the
people of each county on all matters which such county
may now or hereafter be authorized to control by
legislative action. Every such charter shall provide the
form of government of the county and shall determine
which of its officers shall be elected and the manner
of their election, subject to the requirements of Section 1 of Article V of this constitution. It shall provide for the exercise of
all powers vested in, and the performance of all duties
imposed upon counties and county officers by law.
Any such charter may provide for the concurrent or
exclusive exercise by the county, in all or in part of its
area, of all or of any designated powers vested by the
constitution or laws of Ohio in municipalities; it may
provide for the organization of the county as a municipal
corporation; and in any such case it may provide
for the succession by the county to the rights, properties,
and obligations of municipalities and townships
therein incident to the municipal power so vested in
the county, and for the division of the county into districts
for purposes of administration or of taxation or
of both. Any charter or amendment which alters the
form and offices of county government or which provides
for the exercise by the county of power vested
in municipalities by the constitution or laws of Ohio,
or both, shall become effective if approved by a majority
of the electors voting thereon. In case of conflict
between the exercise of powers granted by such
charter and the exercise of powers by municipalities
or townships, granted by the constitution or general
law, whether or not such powers are being exercised at
the time of the adoption of the charter, the exercise of
power by the municipality or township shall prevail.
A charter or amendment providing for the exclusive
exercise of municipal powers by the county or providing
for the succession by the county to any property or
obligation of any municipality or township without the
consent of the legislative authority of such municipality
or township shall become effective only when it
shall have been approved by a majority of those voting
thereon (1) in the county, (2) in the largest municipality,
(3) in the county outside of such municipality, and
(4) in counties having a population, based upon the
latest preceding federal decennial census of 500,000
or less, in each of a majority of the combined total
of municipalities and townships in the county (not included
within any township any part of its area lying
within a municipality.