"Split' congressional districts by region, 1972- 2012 Number of U.S. House districts won by Democratic presidential candidate and a House Republican
First, split-ticket districts were overwhelmingly Republican for the presidency but Democratic when it came to the House (a combined 92.6% of all split-ticket districts in the five election cycles between 1972 and 1988). And second, tickets in Southern districts were far more likely to be split than those in any other region: Of all districts that split their presidential and House votes between 1972 and 1988, 41.2% were from Southern states even though the South accounted for just 31.5% of all House seats. This was well above the shares in any of the other three Census-defined regions. In 1972, two-thirds of all Southern districts split their presidential and House votes; as recently as 1988 more than half still did.
"Split' congressional districts by region, 1972- 2012  | Number of U.S. House districts won by  | Democratic presidential  | Republican presidential  | candidate and a  | candidate and a  | House Republican  | House Democrat  | South  | 75  | 427  | Midwest  | 80  | 208  | Northeast 101  | 157  | West  | 56  | 158  | Source: Pew Research Center analysis of data from CQ Press Polidata the  | Clerk's Almanac of American Politics (2012 edition), Swing State Project (2008). House  | Clerk's office state elections agencies  | PEW RESEARCH CENTER 