A memory circuit includes a first active structure extending along a first direction, a second active structure extending along the first direction, a first conductive structure extending along a second direction, and a lowest via plug layer over the first conductive structure. The first active structure has a shared source portion corresponding to a source node of a first memory cell of the memory circuit and a source node of a second memory cell of the memory circuit. The second active structure has a shared source portion corresponding to a source node of a third memory cell of the memory circuit and a source node of a fourth memory cell of the memory circuit. The first conductive structure electrically connects the shared source portion of the first active structure with the shared source portion of the second active structure.