Brownsville is the principal city of the Brownsville–Harlingen Metropolitan Statistical Area, which is part of the larger Brownsville–Harlingen–Raymondville Combined Statistical Area.

According to the United States Census Bureau, the city has a total area of 83.0 square miles (215.0 km²), making it by far the largest city in the Rio Grande Valley. 80.4 square miles (208.2 km²) of it is land and 2.6 square miles (6.8 km²) of it (3.16%) is water.
There were 38,174 households out of which 50.1% had children under the age of 18 living with them, 59.3% were married couples living together, 20.9% had a female householder with no husband present, and 15.7% were non-families. 13.7% of all households were made up of individuals and 6.7% had someone living alone who was 65 years of age or older. The average household size was 3.62 and the average family size was 3.99.
In the city the population was spread out with 34.6% under the age of 18, 11.2% from 18 to 24, 27.5% from 25 to 44, 17.2% from 45 to 64, and 9.5% who were 65 years of age or older. The median age was 28 years. For every 100 females there were 89.0 males. For every 100 females age 18 and over, there were 82.5 males.
The median income for a household in the city was $24,468, and the median income for a family was $26,186. Males had a median income of $21,739 versus $17,116 for females. The per capita income for the city was $9,762. About 32.4% of families and 36.0% of the population were below the poverty line, giving it the highest poverty rate of any city in the country, including 45.0% of those under age 18 and 31.0% of those age 65 or over.
In 2000, the median gross rent paid for housing in Brownsville was $405 per month. This was the lowest of any city in the United States with more than 100,000 people.
The Census Bureau ranks Brownsville as the most impoverished city in the nation, according to the bureau's 2006 American Community Survey released on Tuesday. via The Brownsville Herald
In 1845, construction of a fort on the Mexican border was commissioned, due to increased instability in the region. Before completion, the Mexican Army began the Siege of Fort Texas, during the first active campaign in the Mexican-American War, between May 3-9, 1846. The first battle of the war occurred on May 8, 1846, when General Zachary Taylor received word of the siege of the fort. They rushed to help, but were intercepted, resulting in the Battle of Palo Alto about 5 miles north of present-day Brownsville. The next morning the Mexican forces had retreated, and Taylor's troops caught up with them, resulting in the Battle of Resaca de la Palma, which was fought within the present city limits. When Taylor finally arrived at the besieged Fort Texas, it was found that 2 soldiers had died, one of which was the fort's commander, Major Jacob Brown. In his honor, General Taylor renamed the fort Fort Brown. An old cannon at the University of Texas at Brownsville and Texas Southmost College marks the spot where Major Brown was fatally wounded.
Contrary to popular belief, however, there is few, if any, evidence that said Fort was called "Fort Texas". In fact, most official correspondence from the time describes the fort as "camp near Matamoros"
The city of Brownsville was originally established late in 1848 by Charles Stillman, and was made the county seat of the new Cameron County on January 13, 1849. The city was originally incorporated by the state on January 24, 1850. This was repealed on April 1, 1852, due to a land ownership dispute between Stillman and the former owners. The state reincorporated the city on February 7, 1853, which remains in effect. The issue of ownership was not decided until 1879, when the U.S. Supreme Court ruled in favor of Stillman.
On July 13 1859, the First Cortina War started. Juan Nepomuceno Cortina would become one of the most important historical figures of the area, and continued to exert a decisive influence in the local events until his arrest in 1875. The First Cortina War ended on December 27, 1859. In May 1861, the brief Second Cortina War took place.
During the Civil War Brownsville was used as a smuggling point for Confederate goods into Mexico, most importantly cotton smuggled to European ships waiting at the Mexican port of Bagdad. Fort Brown was controlled by the Confederates. In November 1863, Union troops landed at Port Isabel and marched for Brownsville to stop the smuggling. Confederate forces abandoned the fort, blowing it up with 8000 pounds of explosives. In 1864, the town was reoccupied by the Confederates under John Salmon 'Rip' Ford. On May 15, 1865, a month after the surrender had been signed at Appomattox Court House, the Battle of Palmito Ranch was fought and won by the Confederades.
On August 13 and 14, 1906, Brownsville was the site of the Brownsville Affair. Racial tensions were high between white townsfolk and black infantrymen stationed at Fort Brown. On the night of August 13th, one white bartender was killed and a white police officer was wounded by rifle shots in the street. Townsfolk, including the mayor, accused the infantrymen as the murderers. Without a chance to defend themselves in a hearing, President Theodore Roosevelt dishonorably discharged the entire 167 member regiment due to their accused "conspiracy of silence". Further investigations in the 1970s found that they were not at fault, and the Nixon Administration reversed all dishonorable discharges.
On September 8, 1926, The Junior College of the Lower Rio Grande Valley (later known as Texas Southmost College) admitted its first class. In 1945 Fort Brown was decommissioned and in 1948 the City and College acquired the land. Between 1945 to 1970 Brownsville population continued to grow gradually, doubled from 25,000 to 52,000 people. In 1991 Brownsville receives a University via the partnership between the University of Texas at Brownsville and Texas Southmost College.
Brownsville was declared an All-America City in the year 2001.
On December 25, 2004, Brownsville had its first instance of measurable snow in 109 years, with 1 1/2 inches, and the first recorded White Christmas. This was part of the 2004 Christmas Eve Snowstorm. The snow was subsequently sold on eBay.
Brownsville has a Council-Manager style of Government. The Mayor and six City Commissioners, two At-Large and four District, serve staggered four year terms. With elections for one At-Large and two District seats every two years. Municipal elections are held on the first Saturday of May in odd numbered years.
As of 2006, the members of the Commission are:
The next regular elections for the City will occur in the following years:
(*) Leo T. Garza will run for the At-Large "B" position again in 2009 as he is completing the remainder of the term left by Ernie Hernandez resigning his commission seat.
The City Commission appoints the City Manager. As of 2006, the City Manager is Charlie Cabler.
The City Commission also appoints a six member Public Utilities Board for a four-year term. Members are limited to two consecutive or non-consecutive terms. The Mayor is an ex-officio member of the Board.
The university opened in 2001 as part of the legislated Regional Academic Health Center program, or RAHC and is phyically located on the campus of the University of Texas at Brownsville. UTSPH - Brownsville is a regional campus of the University of Texas School of Public Health statewide network which offer students a graduate certificate in public health and the Master of Public Health (M.P.H.) graduate degree in a subtropical, multicultural, bilingual, bordertown community. Major public health concerns of the faculty and researchers found here in the Lower Rio Grande Valley Texas include diabetes, tuberculosis, obesity, cardiovascular disease and hepatitis. Other public health concerns include occupation health and safety (especially among the migrant and international communities), behavioral and lifestyle concerns among adolescents (pregnancy, STDs, and otherwise reckless decisions), air and environmental pollution, as well as examining the impacts and issues that are affected as a result of cross-border health, health care and prescription services. To date, over $10 million in research funding has been received by the Brownsville Regional Campus to address these local concerns. http://www.sph.uth.tmc.edu/brownsville).
In addition, Brownsville residents are allowed to apply to magnet schools operated by the South Texas Independent School District, as well as BISD magnet schools. Each BISD high school has a magnet school within the school (example, Homer Hanna High School, a BISD high school, has the district's medical magnet program).
Grades 1-8:
The Roman Catholic Diocese of Brownsville operates area Catholic schools.
Simon Vega operates the "Little Graceland" Museum, replete with Elvis Presley memorabilia in Los Fresnos just north of Brownsville.
of Brownsville was first appointed to the United States District Court in 1961 by President Kennedy, and to the United States Court of Appeals by President Carter in 1978. Garza's biography All Rise: The First Mexican-American Federal Judge was written by Louise Ann Fisch, also a Brownsville native.