The 2015 Waco Showdown was a professional tennis tournament played on outdoor hard courts.
 It was the first edition of the tournament and part of the 2015 ITF Women's Circuit, offering a total of $50,000 in prize money.
 It took place in Waco, United States, on 2–8 November 2015.
Wild Horse Lake is a playa lake located in Texas County, Oklahoma.
 The lake was the location of the infamous Hay Meadow Massacre (July 1888) in which one faction in the county seat fight in Stevens County, Kansas, killed four members of the opposing faction.
 Since the killings took place in what was then No Man's Land, no court had jurisdiction over the crime.
 The lake was also the subject of Oklahoma case law in reference to water appropriations—Depuy V. Hoeme (1980 OK 26, 611 P.2d 228).
Bailey County is a county located in the U.S. state of Texas.
 As of the 2010 census, the population was 7,165.
 This county is east from the New Mexico state line.
 Its county seat is Muleshoe.
 The county was created in 1876 and later organized in 1919.
 It is named for Peter James Bailey, a defender of the Alamo.
 (See List of Texas county name etymologies.)
Houston is a city in Texas County, Missouri, United States.
 The population was 2,081 at the 2010 census.
 It is the county seat of Texas County.
Texas County is a county located in the southern portion of the U.S. state of Missouri.
 As of the 2010 census, the population was 26,008.
 Its county seat is Houston.
 The county was organized in 1843 as Ashley County, changing its name in 1845 to Texas, after the Republic of Texas.
The 2016 Waco Showdown was a professional tennis tournament played on outdoor hard courts.
 It was the 2nd edition of the tournament and part of the 2016 ITF Women's Circuit, offering a total of $50,000 in prize money.
 It took place in Waco, Texas, United States, on 7–13 November 2016.
Waco ( ) is a city which is the county seat of McLennan County, Texas, United States.
 It is situated along the Brazos River and I-35, halfway between Dallas and Austin.
 The city had a 2010 population of 124,805, making it the 22nd-most populous city in the state.
 The US Census 2016 population estimate is 134,432 The Waco Metropolitan Statistical Area consists of McLennan and Falls Counties, which had a 2010 population of 234,906.
 Falls County was added to the Waco MSA in 2013.
 The US Census 2016 population estimate for the Waco MSA is 265,207.
The Waco Showdown is a tournament for professional female tennis players played on outdoor hard courts.
 The event is classified as a $50,000 ITF Women's Circuit tournament and has been held in Waco, Texas, United States, since 2015.
The following is a list of Texas county seat name etymologies, taken from the "Handbook of Texas".
 A separate list of Texas county name etymologies, covering Texas counties instead of its county seats, is also available.
Rockwall County is a county in the U.S. state of Texas.
 At 149 square miles, Rockwall County has the smallest area of any Texas county.
 As of the 2014 U.S. census estimate, its population was 87,809.
 Its county seat is Rockwall.
 The county and city are named for a wall-like subterranean rock formation that runs throughout the county.

Question: The 2016 Waco Showdown took place in the county seat of what Texas county?
Answer: McLennan