An integrated circuit structure includes: an integrated circuit structure includes: a first plurality of cell rows extending in a first direction, and a second plurality of cell rows extending in the first direction. Each of the first plurality of cell rows has a first row height and comprises a plurality of first cells disposed therein. Each of the second plurality of cell rows has a second row height different from the first row height and comprises a plurality of second cells disposed therein. The plurality of first cells comprises a first plurality of active regions each of which continuously extends across the plurality of first cells in the first direction. The plurality of second cells comprises a second plurality of active regions each of which continuously extends across the plurality of second cells in the first direction. At least one active region of the first and second pluralities of active regions has a width varying along the first direction.