As utility corridors become increasingly congested AC interference on pipelines due to collocation with high voltage AC (HVAC) transmission powerlines continues to be a growing concern. Many pipeline operators have large quantities of existing pipeline infrastructure that has not been fully assessed to determine whether they are at risk due to AC interference. The primary risks on these pipelines under powerline steady-state conditions are safety and AC corrosion.This paper summarizes an AC interference risk ranking program implemented by one of the largest combination gas and electric utilities in the United States on over 6400 miles of existing transmission piping. Much of the infrastructure is aging – over 50 years old with some dating back approximately 100 years. The scope of this project is to identify the transmission pipelines that are at greatest risk due to steady-state AC interference to prioritize them based on the severity of risk and to determine what further action is required. Once the ranking is completed it is envisioned that AC interference studies and the design and implementation of mitigation and monitoring systems will be performed on the at risk pipeline systems in order of priority as part of a multi-year program.Keywords:AC Mitigation AC Interference AC Corrosion High Voltage AC (HVAC) Transmission Powerlines Risk Ranking Gas Transmission Pipelines.