Wis. Stat. § 2.04
The counties now or hereafter organized upon the westerly shore of Lake Michigan shall have jurisdiction in common of all offenses committed on the lake. The counties now or hereafter organized on the shores of Green Bay shall have jurisdiction in common of all offenses committed on Green Bay. The counties now or hereafter organized on the southerly shore of Lake Superior shall have jurisdiction in common of all offenses committed on the lake. The counties now or hereafter organized on the easterly shore of the Mississippi River shall have jurisdiction in common of all offenses committed on the river. The counties now or hereafter organized on the shores of Lake Winnebago shall have jurisdiction in common of all offenses committed on any part of the lake. The counties now or hereafter organized on the easterly shore of the St. Croix River or lake shall have jurisdiction in common of all offenses committed on any part of the river or lake; when 2 or more counties are now or hereafter organized on the shores of any inland water of this state, as defined in s. 29.001(45), the counties shall have jurisdiction in common of all offenses committed on any part of the inland water; and all offenses committed against this state on any part of the waters may be heard and tried in any of the counties having common jurisdiction over the waters where the offense may be committed in which legal process against the offender is first served and may be alleged and shall be conclusively deemed to have been committed within the county; and all civil process from any of the counties may be executed within and upon the waters that are within the jurisdiction of the county. In the construction of this section all wharves and piers are part of the land with which they are connected.
Wis. Stat. § 2.04