In 1845, the first election was held on the issue of Texas' annexation to the United States with, on March 30, 1846, Dallas County being organized. On April 18, Dallas became the temporary county seat, and a tiny log cabin served as the first courthouse.

Dallas was incorporated as a town in 1856 with two thousand people living in Dallas by 1860. However, 1860 was a tumultuous year. July of that year, a fire broke out in the square, destroying most of the buildings in the business district and the civil war of 1861 hit the town hard. Although being far from the theater of war times were rough. Prices for basic household necessities rose dramatically. The newspaper stopped printing for almost a year.

Remaining fairly prosperous at the end of the war Dallas grew during the reconstruction years, unlike other Southern towns that had to rebuild first.

Texan slaves were freed on June 19, 1865. Many African Americans came to Dallas after the war because the city remained prosperous compared to other Southern towns.

On July 16, 1872, the first passenger train, the Houston and Texas Central, steamed into Dallas. In 1873, the Texas and Pacific came. With the arrival of the trains, the population soared, from 3,000 in early 1872 to more than 7,000 in September of the same year.

In 1871, the first volunteer fire company, Dallas Hook and Ladder Company #1, was organized. Gas lamps lighted Dallas streets in 1874. The first telephone line linked the water company to the fire station in 1880.

In 1890, Dallas annexed the city of East Dallas, which had a larger geographical area than that of Dallas. This was followed in 1903 when Oak Cliff, a city on the other side of the Trinity, was annexed.

In 1915, Southern Methodist University opened its doors using $300,000 and 666.5 acres of land provided by the Methodist church.

World War I brought Dallas to the forefront of aviation. Love Field was established as an aviation training ground which the city bought Love Field in 1927 to operate as its municipal airport.

However the depression hit Dallas hard, but not as hard as other US cities. By 1931, more than 18,000 people were unemployed. However even during the closing of the banks, many businesses continued to operate as usual. The reason for this was oil.

In 1930, Columbus Marion "Dad" Joiner struck oil 100 miles east of Dallas. Oil was booming in East Texas, and Dallas was in the perfect position to benefit from this. In the first two months of 1931, twenty-eight businesses either formed or moved to Dallas for the oil.

In 1948 Dallas started to attract large multinational companies to the area. By 1974 more than 626 companies had their headquarters in Dallas. The opening of DFW International Airport in 1974 aided the growth of the Metroplex.

In 1960, Dallas was home to two professional football team: the Dallas Cowboys and the Dallas Texans (in 1962, the Texans were moved to Kansas City and renamed the Chiefs). 1972, baseball came to Dallas with the Texas Rangers. The Mavericks brought basketball in 1980. Soccer came in 1984 with the Sidekicks. In 1993, professional hockey came with the Dallas Stars.

Of course November 22, 1963, brought a defining event in the history of Dallas. The assassination of President John F. Kennedy in Dealey Plaza traumatized before the city and the nation. Dallas has never forgot. In 1970, the Kennedy Memorial was erected, and in 1989, the Sixth Floor Museum opened.

The US census of 2000 listed the Population of the City of Dallas as 1,188,580.