Every day, thousands of miles of pipelines underground quietly and safely deliver energy to keep our homes comfortable and well-lit. Williams owns and operates the nation’s largest and most reliable interstate natural gas transmission pipeline, called Transco.

Transco is not just one pipeline, but an artery of about 10,000 miles of pipelines connecting an energy corridor spanning from south Texas to New York City. This infrastructure network transports about 15 percent of the natural gas consumed in the U.S., making it the largest of four interstate pipelines operated by Williams.
Much of the electricity that consumers use in their homes and businesses in the United States originates from natural gas transmission pipelines like Transco. Natural gas is also a critical energy source for industrial and commercial uses as well as in businesses and households for heating, cooking and hot water.
Past and Future
To fully appreciate the astounding level of growth on Transco, it’s important to not lose sight of where we started. When the Transco pipeline was placed into service in 1949, it was touted as the longest pipeline in the world and the largest single-project construction venture ever attempted.
Throughout its 70-year history, the pipeline has undergone multiple expansions to meet growing energy demand. As the importance of clean energy grows, Transco is positioned to play a critical role in the energy transition.
In fact, a proposed expansion called Regional Energy Access is being designed in a manner that is adaptable to future renewable energy sources like clean hydrogen and RNG blending, thereby providing the necessary and critical infrastructure needed to meet clean energy demand for generations to come.
Safety and Reliability
Transco’s steel pipes vary between 24” and 48” inches in diameter and undergo rigorous maintenance and inspection processes – this includes continuous system and remote-control monitoring, aerial and control valve inspections, leak surveying, and pipeline markings. Additionally, the use of innovative technology such as pressure and temperature sensors, 100% weld x-rays, smart pigs for cleaning, clearing and inspecting as well as strength testing, protective coating and cathodic protection is applied.
Through Transco’s unique network of interconnections with other pipelines and strategic storage reserves the pipeline has the capability of allowing for multiple pathways to reroute natural gas deliveries to customers.
When temperatures drop during the winter, preparation is a huge component of Transco’s operational success. Our teams conduct tabletop exercises to simulate a potential pipeline outage during a winter cold snap to improve how the natural gas pipeline system and the electric grid work together, ensuring that the pipeline system continues to operate reliably and safely, even in severe weather conditions.
The pipeline transports natural gas to 13 states serving Williams’ customers in the Southeast, Mid-Atlantic and Northeast. From there it goes to local distribution companies that supply residence and businesses for heating and cooking as well as large commercial and industrial users and electric power plants. The pipeline system capacity is 17.9 million dekatherms per day which is enough to provide natural gas to more than 38 million U.S. households on an average January day.
Transco Facts
- Transco is the largest interstate pipeline in the U.S.
- The pipeline transports 15% of the natural gas in the U.S.
- The first delivery on Transco was in 1950.
- Transco has operations in 13 states, including major metropolitan areas in New York, New Jersey and Pennsylvania.
- Throughout its network, Transco has more than 1,160 employees.
- 57 compressor facilities that help move gas along a 10,000-mile pipeline.
- Transco’s system capacity is 17.9 million dekatherms per day.
What does 17.9 million dekatherms mean?
- Enough energy to provide for the natural gas needs of 85.6 million U.S. households or 2/3 of all the households in the United States.
- Enough to provide natural gas to 100% of U.S. residential gas consumers on an average day.
Sources:
- Historical Households Tables (census.gov)
- Residential Consumption of Natural Gas (Summary) (eia.gov)
- U.S. Number of Natural Gas Consumers (eia.gov)
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