Question: Harrods Creek, Louisville merged with what most populous county in Kentucky in 2003?

Context paragraphs:
Griffytown, Louisville: Griffytown is a neighborhood of Louisville, Kentucky located in unincorporated Jefferson County, along Old Harrods Creek Road.  Streets within its boundaries include: Bellewood Road, Robert Road, Church Lane, Lincoln Way, Cox Lane, Malcolm Avenue, Plainview Avenue and Booker Road.  In 1879, a freed slave named Dan Griffith, an African American, purchased the land he had been living on in the area and the neighborhood appears to be named for him.  The neighborhood was redeveloped in the 1970s through urban renewal and remains predominantly African American, although a number of families of other races live there as well.

Harrods Creek, Louisville: Harrods Creek is a neighborhood of Louisville, Kentucky centered near Harrods Creek at the intersection of River Road and Wolf Pen Branch Road.  It is roughly bordered by the Ohio River to the west and US 42 to the east.  Its ZIP code is 40027.  Formerly an unincorporated community, it was designated a neighborhood of Louisville when the city merged with Jefferson County in 2003.

Louisville, Harrods Creek and Westport: The Louisville, Harrods Creek and Westport (LCH&W) may refer to either of:

Louisville, Harrods Creek and Westport Railroad: The Louisville, Harrods Creek and Westport Railroad was a 19th-century railway company in the U.S. state of Kentucky.  It was formed from the failed Louisville, Harrods Creek and Westport Rail"way" in 1879, gave up its predecessor's hope of reaching Westport or beyond, and simply continued service along the existing narrow gauge railway line between Fulton Street and Harrods Creek until the company's 1881 purchase by the Louisville and Nashville Railroad.

Salem County, New Jersey: Salem County is a county located in the U.S. state of New Jersey.  Its western boundary is formed by the Delaware River and it has the eastern terminus of the Delaware Memorial Bridge, connecting to New Castle, Delaware.  Its county seat is Salem.  The county is part of the Delaware Valley area.  As of the 2016 Census estimate, the county's population was 63,436, making it the state's least populous county, representing a 4.0% decrease from the 66,083 enumerated at the 2010 Census, in turn increasing by 1,798 (+2.8%) from the 64,285 counted in the 2000 Census, retaining its position as the state's least populous county.  The most populous place was Pennsville Township, with 13,409 residents at the time of the 2010 Census.  Lower Alloways Creek Township covers 72.46 sqmi , the largest total area of any municipality.

Jefferson County, Kentucky: Jefferson County is a county located in the U.S. state of Kentucky.  As of the 2010 census, the population was 741,096.  It is the most populous county in Kentucky and is more than twice as large as the second most populous, Fayette.  The county was formed in 1780 and named for future President Thomas Jefferson, who was Governor of Virginia at the time.

Otter Creek Outdoor Recreation Area: Otter Creek Outdoor Recreation Area (formerly Otter Creek Park) is a 2,600 acre (11 km²) riverfront park in Meade County, Kentucky.  The park is located near Muldraugh and Fort Knox, along State Highway 1638, near U.S. 31W.  Although it is located outside Louisville, the park was long operated by the city of Louisville and, after the 2003 merger of the city and Jefferson County, Louisville Metro Government.  Both entities attempted to give or sell the park to Meade County and the Commonwealth of Kentucky at various times over the years, most recently in 2004.  The park closed in 2009 and reopened in 2011.  It is now operated by the Kentucky Department of Fish and Wildlife Resources.

Louisville, Harrods Creek and Westport Railway: The Louisville, Harrods Creek and Westport Railway was a 19th-century railway company in the U.S. state of Kentucky.  Its first president was James Callahan.  It was organized by Louisvillian businessmen in 1870, began construction and operation of the narrow gauge railway in 1872, and failed in 1879 owing the era's Long Depression.  The line then gave up hope of connecting to Westport or beyond and reincorporated as the more modest Louisville, Harrods Creek and Westport Rail"road", which simply continued service along the existing track.

Wolf Creek, Louisville: Wolf Creek is a neighborhood in far eastern Jefferson County, Kentucky, United States.  Located directly east of Louisville along the Ohio River, Wolf Creek is bordered by Harrods Creek, Green Spring and Little Goose Creek.  Its zip code is 40241.  The neighborhood is quietly nestled amongst rolling hills and features heavy tree density, many small tributaries and natural wildlife.

Harrods Creek Baptist Church and Rev. William Kellar House: Harrods Creek Baptist Church and Rev. William Kellar House

Supporting paragraphs: Harrods Creek, Louisville Jefferson County, Kentucky
Answer: Jefferson County