Thirlage Act 1799 (c. 55)

13 If mill and lands be within different counties, application to be made to the sheriff where the mill is situate. E+W+S

And whereas it may happen that a mill and some of the lands thirled to it may be within different counties: in such case the application shall be made to the sheriff of the county in which the mill is situated, before whom the parties concerned who live without his jurisdiction may be cited by virtue of letters of supplement in common form.