Danbury is on Spur 28 two miles off State Highway 35 and five miles northeast of Angleton in Brazoria County. Until the coming of the Missouri Pacific Railroad in 1905–06 this area was populated only by a few ranchers and farmers. The railroad gave access to hundreds of acres of rich farmland that had previously been almost inaccessible, and several towns grew up along the route. It is said the railroad construction workers gave the town its name in honor of D. J. "Uncle Dan" Moller, an area rancher who often entertained them at night with music and tall tales. Other sources say it was named for a Daniel T. Miller. Land promoters bought up large tracts and advertised in the North and Midwest. Settlers began to arrive, and a hotel was built to accommodate them. A demonstration farm garden was planted. Businesses began to open, including a general store, in which a post office was established in 1909.
Since most of the newcomers engaged in truck farming, docks were built on Austin Bayou, two miles southeast of Danbury, to ship produce by boat to Galveston. Watermelons, strawberries, cabbages, and onions went by train to Chicago, New York, and other cities in the north. When oil was found at nearby Hoskins Mound, it, too, was shipped by rail from Danbury. By 1916 most of the northerners had left, discouraged by freezes, floods, and storms; Czech farmers began to move into the area.
The first school in Danbury was held in a private home before 1909, when a one-room, frame school was built. More rooms were added in 1912 and 1917, and in 1920 the first brick school was constructed. The old frame building was divided in half and used for many years by the town's Protestants and Catholics. In 1990 both the Catholics and the Baptists had substantial buildings in Danbury, and major school-construction programs had provided modern facilities for the increasing number of students.
An airfield was located in Danbury during World War I. Planes from Ellington Field landed there, then flew on to West Columbia as part of the cross-country flight-training program. Danbury was incorporated in 1960, with a mayor and council form of government. In 1990 the chief industries of the area were rice farming and cattle ranching, both of which began long before the town sprang up, and declining oil production; a catfish farm was in operation. Danbury had a population of 1,447 in 1990 and 1,611 in 2000.