Houston has always been known for energy and oil & gas. An area located west of downtown known as the Energy Corridor is home to many of these companies. There are currently twenty-one Fortune 500 companies headquartered in Houston, most of them related to Oil & Gas/Energy.
Included in the Top 200 are Phillips 66, ConocoPhillips, Plains All American Pipeline, Baker Hughes and Halliburton. Upstream, downstream, drilling, pipelines, and oilfield services. These companies have large corporate counsel offices and equally large outside counsel with multiple law firms.