The Houston Police Department (HPD) is the primary law enforcement agency serving the City of Houston, Texas, United States and some surrounding areas. With approximately 5,300 officers and 1,200 civilian support personnel it is the fifth-largest municipal police department, serving the fourth-largest city in the United States. Its headquarters are at 1200 Travis in Downtown Houston. HPD's jurisdiction often overlaps with several other law enforcement agencies, among them the Harris County Sheriff's Office and the Harris County Constable Precincts. HPD is the largest municipal police department in Texas. History Beginnings Houston was founded by brothers Augustus and John Kirby Allen in 1836 and incorporated as a city the next year, 1837. As the capital city of the Republic of Texas, it quickly grew, and so did the need for a cohesive law enforcement agency. The Houston Police Department was founded in 1841. The first HPD badge issued bore the number "1." The early part of the 20th century was a time of enormous growth for both Houston and for the Houston Police Department. Due to growing traffic concerns in downtown Houston, the HPD purchased its first automobile in 1910 and created its first traffic squad during that same year. Eleven years later, in 1921, the HPD installed the city's first traffic light. This traffic light was manually operated until 1927, when automatic traffic lights were installed. As Houston became a larger metropolis throughout the 1930s and 1940s, the HPD found itself growing and acquiring more technology to keep up with the city's fast pace. The first homicide division was established in 1930. During that same year, the HPD purchased newer weapons to arm their officers: standard issue .44 caliber revolvers and two Thompson submachine guns. In 1939, the department proudly presented its first police academy class. The Houston Police Officers Association (HPOA) was created in 1945. This organization later became the Houston Police Officers Union. The first African American woman police officer on the force, Margie Duty, joined the HPD in 1953, starting in the Juvenile Division. During the 20th century, the HPD enforced an oppressive racial system that targeted blacks for harassment and failed to protect the black community. The HPD zealously enforced racial segregation in Houston. In 1967, a civil rights protest at Texas Southern University turned into what police say was a riot. One officer was killed and nearly 500 students were arrested. It was as a