ONEOK, Inc. engages in gathering, processing, fractionation, storage, transportation, and marketing of natural gas and natural gas liquids (NGL) in the United States.

It operates through four segments: Natural Gas Gathering and Processing, Natural Gas Liquids, Natural Gas Pipelines, and Refined Products and Crude.

The company owns natural gas gathering pipelines and processing plants in the Mid-Continent and Rocky Mountain regions.

It also provides midstream services to producers of NGLs. The company owns NGL gathering and distribution pipelines in Oklahoma, Kansas, Texas, New Mexico, Montana, North Dakota, Wyoming, and Colorado; terminal and storage facilities in Kansas, Missouri, Nebraska, Iowa, and Illinois; NGL distribution pipelines in Kansas, Missouri, Nebraska, Iowa, Illinois, and Indiana; and transports refined petroleum products, including unleaded gasoline and diesel from Kansas to Iowa, as well as owns and operates truck- and rail-loading, and -unloading facilities connected to NGL fractionation, storage, and pipeline assets.

In addition, it transports and stores natural gas through regulated interstate and intrastate natural gas transmission pipelines, and natural gas storage facilities.

Further, the company owns and operates a parking garage in downtown Tulsa, Oklahoma; and leases excess office space and rail cars.

Additionally, it transports, stores, and distributes refined products, NGLs, and crude oil, as well as conducts commodity-related activities, including liquids blending, fractionation, and marketing activities.

It serves integrated and independent exploration and production companies; NGL and natural gas gathering and processing companies; crude oil and natural gas production companies; utilities; industrial companies; propane distributors; municipalities; ethanol producers; and petrochemical, refining, and NGL marketing companies.

ONEOK, Inc. was founded in 1906 and is headquartered in Tulsa, Oklahoma.