La Porte, founded in 1892, is on the northwest shore of Trinity Bay, the inland extension of Galveston Bay; it covers an area of fifteen square miles in southeastern Harris County. It was established as a real estate venture by a group of men including A. M. and J. H. York, I. R. Holmes, and T. W. Lee, who chose the French word for "door" as its name. By 1900 La Porte had a population of 537. St. Mary's Seminary was founded there the same year by Bishop Nicholas A. Gallagher and remained there until 1954, when it was moved to Houston. In 1915 La Porte suffered from two major disasters-a fire that destroyed all of the downtown business district and a tremendous hurricane. During the 1920s and 1930s La Porte gained national attention because of Sylvan Beach Amusement Park, where a number of big bands, including those of Rudy Vallee, Phil Harris, and Benny Goodman, performed at dances and beauty contests. Until World War II La Porte continued as a sleepy little village, with only Sylvan Beach and the summer residents at Bay Ridge sustaining the economy. Shipyards in the area and the growing petrochemical industry along the channel provided employment for new residents.
The opening of the La Porte-Baytown tunnel in 1953 and the coming of the Lyndon B. Johnson Space Center and Bayport Channel helped the growth and prosperity of the city. By 1970 La Porte had a population of 7,149. The consolidation of Lomax with La Porte in 1980 and the growth of Fairmont Park further enhanced the prosperity of the city. Although the population of La Porte continued to grow during the 1980s, its residents still considered it a small recreational community. In 1990 La Porte had a population of 27,910. Plans were being made to revive the Sylvan Beach area, which had been battered by several hurricanes over the previous fifty years. Proposals included construction of a large beachfront hotel. By 2000 the population was 31,880, and in 2010 it was 33,800.