Brooks County is a county in Texas, United States, and Falfurrias is its county seat. Its population was 7,076, approximately 88% Latino per the 2020 census. It is one of Texas's poorest counties.

The county is named for James Abijah Brooks, one of the “Four Captains” who modernized the Texas Rangers. He retired to Falfurrias, served two terms as state representative, lobbied successfully for the county's creation, and served thirty years as county judge.

Brooks County has several large ranches, including Mariposa Ranch and the King Ranch, both in the east. The county's largest employer is the Falfurrias Border Patrol interior checkpoint on US 281, built in 1994 outside the city limits and significantly enlarged in 2019.

Brooks County is "the nation's busiest corridor for illegal immigration;" and a tracking camera records up to 150 people going through one piece of property nightly. More illegal migrants die in Brooks County than in any other county in America. Although it is about 80 miles (130 km) north of the border, it is on a main route headed toward San Antonio and Dallas from Mexico. The documentary Missing in Brooks County called the county the "epicenter" of America's immigration problem. It was called a "Death Valley" for migrants in 2014.

Many migrants attempt to bypass the Falfurrias United States Border Patrol interior checkpoint by hiking some 35 miles (56 km) around it through the open, dry terrain local ranchers call "the killing fields". The terrain is flat, sandy, and hard to walk on. The lack of landmarks can be disorienting, causing some migrants to walk in circles. Summer, with bright sun and high temperatures regularly exceeding 100 °F (38 °C), can lead to dehydration, sunstroke, and death. Those attempting the trip with smugglers can be subject to mistreatment, including ransom and rape.

Migrants in distress call 911, and there typically are "a few dozen cellphone calls a day". Between 2016 and 2018, there were 722 calls leading to Border Patrol rescues, usually resulting in arrest or deportation. The Border Patrol apprehends between 60 and 70 undocumented immigrants daily. Tom Slowinski, in charge of the Falfurrias Border Patrol facility in 2019, said, "No other checkpoint anywhere on the Southwest border catches more alien smuggling cases than this checkpoint right here."

Illegal immigrant death is also a significant issue. Between 2009 and 2018, over 600 bodies were recovered. Most are not identified. Consequently, Brooks County has been described as "the biggest cemetery in America.” According to Brooks County Deputy Sheriff Benny Martinez, the multiple of found to unfound bodies is probably 5 to 10 times. One estimate is that there are over 2000 unfound bodies. Consistent with these estimates, the number of reported missing persons exceeds the number of bodies recovered.

The illegal immigration issue is a significant challenge for Brooks County. Migrants bypassing the Border Patrol checkpoint sometimes damage property, tear down fences, steal, or threaten residents of the ranches through which they trespass. Residents resent the reputation the Border Patrol checkpoint and migrant deaths have given their county. Most importantly, the cost of addressing these issues has overwhelmed county resources, and the county has been unsuccessful in getting additional federal help for the local impact of a significant national issue.