Connecticut's 12th State Senate district elects one member of the Connecticut State Senate.

The district consists of the towns of Branford, North Branford, Durham, Guilford, Killingworth, and Madison.

[1] Its current senator is Christine Cohen.

The district boundaries established after the 2010 census are the same as those established after the 2000 census.

[2] At this point redistricting caused Fairfield County to be represented in the Senate by the 25th and 26th district.