Kentucky's 4th congressional district is a congressional district in the U.S. state of Kentucky. Located in the northeastern portion of the state, it is a long district that follows the Ohio River. However, the district is dominated by its far western portion, comprising the eastern suburbs of Louisville and Northern Kentucky, the Kentucky side of the Cincinnati area.

The majority of voters live in the booming suburban Cincinnati counties of Boone, Kenton, and Campbell, which includes such suburbs as Fort Mitchell, Covington, Florence, Newport, and Fort Thomas. The next-largest population center is the northeastern suburbs of Louisville. It stretches as far south as northern portions of the city of Bardstown.

The district is currently represented by Republican Thomas Massie, who was elected in a special election in 2012 to succeed Republican Geoff Davis, who resigned on July 31, 2012, citing family concerns.

The 4th was one of the first areas of Kentucky to turn Republican outside of traditionally Republican south-central Kentucky; it has been in GOP hands for all but six years since 1967. Its politics are dominated by Republicans in the wealthy Cincinnati suburbs, which have swelled with former Cincinnati residents since the early 1960s. Between them, Boone, Kenton and Campbell counties have as many people as the rest of the district combined. As a measure of how much the Cincinnati suburbs have dominated the district, when Massie took office, he became the first congressman from the district's eastern portion in 45 years. Nonetheless, Democrats still hold state and local offices in rural counties.

Until January 1, 2006, Kentucky did not track party affiliation for registered voters who were neither Democratic nor Republican.^[5] The Kentucky voter registration card does not explicitly list anything other than Democratic Party, Republican Party, or Other, with the "Other" option having a blank line and no instructions on how to register as something else.^[6]

• Kentucky's congressional districts
• List of United States congressional districts