Lamar County is a county located in the U.S. state of Texas. As of the 2010 census, its population was 49,793. Its county seat is Paris. The county was formed by the Congress of the Republic of Texas on December 17, 1840 and organized the next year. It is named for Mirabeau Buonaparte Lamar, the second president of Texas.Lamar County comprises the Paris, TX Micropolitan Statistical Area.Lamar County, once heavily Democratic, is now represented in the Texas House of Representatives by the Republican Gary VanDeaver of New Boston, Texas. Republican Representative Marsha Farney, reared in Lamar County, represents District 20, which includes the northern portion of Williamson County in the Austin suburbs.GeographyAccording to the U.S. Census Bureau, the county has a total area of, of which is land and (2.8%) is water.