As part of Forebears' program of listing demographics statistics by surname, today we release the share of surname bearers who are registered with the two dominant political parties in The United States: The Democratic Party and The Republican Party.

You can view a surname's political affiliation data by searching for a surname and scrolling down to the demographics section; or by viewing the list of most Republican and Democratic affiliated surnames.

The results show that there are strong leanings for people with certain surnames to affiliate with one of the two parties. At the extreme there are a number of surnames, whose bearers are registered with one party, from a sample in excess of one-hundred people. In the case of the surname Matherne, over 90% of bearers are registered with The Republican Party, from a sample of 1,199 people. The Democratic Party has a much stronger affiliation from a number of surnames; with over 98% of 1,149 people with the Barboza surname registered with the party.

The data also shows strong differences between the ethnic and national backgrounds of Americans. Surnames with a strong association with The Republican Party are mostly of a German or Dutch background; with smaller representation from people with a Belgian, French and Luxembourgish origin. While Democratic registrations skews heavily towards people of a Latin American and Jewish background.

These results support findings from Gallup, which found that 71% of Americans share similar political views to their parents. From this new data arranged by surname, it appears there is significant differentiation among families as to the inheritance of political beliefs.

The data was compiled from state voters files, which list personal details and the party a voter is registered to vote for in primaries. In total the data includes over 70 million people and has been used to produce political affiliation statistics for over 650,000 surnames. Statistics have been listed for surnames where there is a sample size of four or more.

It should be noted that there is a difference between registered voters and voters in elections. Millions of Americans vote in elections, but are not registered. This may be due to sitting on the fence, disinterest or because their state does not register voters.