In 1881, the Gulf, Colorado and Santa Fe Railway extended its tracks through central Texas, buying 360 acres (1.5 km2) a few miles southwest of a small farming community known as Palo Alto, which had existed since about 1872.

By 1884, the town had grown to include about 350 people, served by five general stores, two gristmills, two cotton gins, two saloons, a lumberyard, a blacksmith shop, and a hotel.

Killeen expanded as it became an important shipping point for cotton, wool, and grain in western Bell and eastern Coryell Counties.

Around 1905, local politicians and businessmen convinced the Texas legislature to build bridges over Cowhouse Creek and other streams, doubling Killeen's trade area.

Laborers, construction workers, contractors, soldiers, and their families moved into the area by the thousands, and Killeen became a military boomtown.

The opening of Camp Hood radically altered the nature of the local economy, since the sprawling new military post covered almost half of Killeen's farming trade area.

The loss of more than 300 farms and ranches led to the demise of Killeen's cotton gins and other farm-related businesses.

Killeen then suffered a recession when Camp Hood was all but abandoned after the end of the Second World War, but when Southern congressmen got it established in 1950 as a permanent army post, the city boomed again.

[citation needed] In addition to shaping local economic development after 1950, the military presence at Fort Hood also changed the city's racial, religious, and ethnic composition.

The city's first resident Catholic priest was assigned to the St. Joseph's parish in 1954, and around the same time, new Presbyterian and Episcopal churches were built.

Troop cutbacks and transfers in the mid-1950s led to another recession in Killeen, which lasted until 1959, when various divisions were reassigned to Fort Hood.

On October 16, 1991, George Hennard murdered 23 people and then committed suicide at the Luby's Cafeteria in Killeen.

[citation needed] By 2000, the census listed Killeen's population as 86,911, and by 2010, it was over 127,000, making it one of the fastest-growing areas in the nation.

[7] On November 5, 2009, only a few miles from the site of the Luby's massacre, a gunman opened fire on people at the Fort Hood military base with a handgun, killing 13 and wounding 32.

In 2011, Killeen got media attention from a new television series called Surprise Homecoming, hosted by Billy Ray Cyrus, about military families who have loved ones returning home from overseas.

[8][9] Killeen is located in western Bell County and is bordered to the north by Fort Cavazos and to the east by Harker Heights.

Killeen is 16 miles (26 km) west of Belton, the county seat and nearest access to Interstate 35.

In 2007, Coldwell Banker rated Killeen the most affordable housing market in the United States, with an average cost of $136,725.

[22] Central Texas College was established in 1965 to serve Bell, Burnet, Coryell, Hamilton, Lampasas, Llano, Mason, Mills, and San Saba Counties, in addition to Fort Cavazos.

Television stations include KAKW (Univision O&O), KCEN (NBC), KNCT (The CW), KWTX (CBS/Telemundo), KWKT (Fox), KXXV (ABC), and KAMU (PBS).

Killeen is served by 2 AM radio stations: KTEM and KTON; and 17 FM stations: KBDE, KIIZ, KJHV, KLFX, KLTD, KMYB, KNCT, KOOC, KOOV, KRGN, KRYH, KSSM, KUSJ, KVBM, KVLT, KWTX, and WACO.

In the metro area's partner city, Temple, there is Amtrak inter-city passenger train service on the Texas Eagle.

Currently, the department operates by three 24-hour shifts and provides emergency services from 8 staffed fire stations strategically placed throughout the city.

With continued growth and expansion, Fire Station #9 was completed in 2017 and provides service the southwest area of town.

The Killeen rates are calculated using the estimated 2008 population figure of 115,906 as provided by the Texas Department of Public Safety.

The perpetrator, George Hennard, drove his pickup truck through the front window of the restaurant, and immediately shot and killed 23 people, and wounded 27 others before fatally shooting himself.