FACTBOX: Kentucky and its presidential primary

(Reuters) - Barack Obama and Hillary Clinton face off in Kentucky on May 20 in the state-by-state contest to determine the Democratic nominee to face Republican John McCain in the November presidential election.

Following are some facts about the Bluegrass State:

* Voting begins at 6 a.m. EDT (1000 GMT) and ends by 7 p.m. EDT (2300 GMT). Results are expected shortly after.

* Public opinion polls show Clinton leading Obama by a wide margin, though the state's 31 electoral votes are unlikely to significantly affect the outcome of the Democratic race.

* Kentucky has voted Republican in the last two presidential elections and is not expected to be a contested state this November.

* Kentucky is famous as the home of bourbon whiskey, bluegrass music and the Kentucky Derby horse race. Tobacco farming and coal mining remain important industries in this largely rural state.

* Governors in Kentucky must swear that they have not participated in a duel.

(Compiled by Andy Sullivan, editing by David Alexander)

SOURCES: Kentucky State Board of Elections; U.S. Census Bureau; Almanac of American Politics

(To read more about the U.S. political campaign, visit Reuters "Tales from the Trail: 2008" online at blogs.reuters.com/trail08/)