[3] The county is named for James Abijah Brooks, one of the “Four Captains” who modernized the Texas Rangers.

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.

[5] Brooks County is "the nation's busiest corridor for illegal immigration;"[3] and a tracking camera records up to 150 people going through one piece of property nightly.

[6] 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.

[8] 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".

Summer, with bright sun and high temperatures regularly exceeding 100 °F (38 °C), can lead to dehydration, sunstroke, and death.

Migrants bypassing the Border Patrol checkpoint sometimes damage property, tear down fences, steal, or threaten residents of the ranches through which they trespass.

The Border Patrol does not answer 911 calls or recover or bury dead bodies, so that falls on the county.

The Brooks County Sheriff's Department, which once had 12 deputies, now has two, who work 48 hour weeks in aging vehicles with no health insurance.

[13] In contrast, the Border Patrol has in its Brooks County facility, the largest border checkpoint in the country, modern equipment, dozens of 4-wheel drive trucks with infrared night-vision capabilities, a car wash, a helicopter, a blimp, a canine team, and 300 agents.

While Texas has become a Republican Party stronghold in the 21st century, Brooks County remains solidly Democratic.

The only Republican to have carried Brooks County was State Comptroller Susan Combs, who ran unopposed for re-election in 2010.