Boeing has opened a fourth 737 MAX final assembly line at its factory in Everett, Washington, marking the first time in more than 50 years that the 737 has been built outside Renton.
Production began on the first aircraft on July 6, 2026, with Boeing formally marking the opening of the new North Line four days later. The line occupies space in the Everett factory that was originally built for widebody aircraft, including the 747.
The first 737 moving through the line is a 737 MAX 10. Boeing did not publicly identified the customer for that airplane.
The new line is designed around the same production process used at Boeing’s three existing 737 lines in Renton, about 40 miles south of Everett. Boeing said that should allow teams at both sites to share procedures and production improvements.
The North Line will not immediately result in a sharp increase in monthly output. Boeing plans to use the first aircraft for low-rate initial production, giving workers time to test the line, complete regulatory and compliance work and make changes before output increases.
The company is currently raising 737 production from 42 to 47 aircraft a month. Once the Renton lines stabilize at that level, the Everett line is expected to provide the additional capacity needed to reach 52 aircraft a month and potentially higher rates later.
Boeing has more than 4,000 737 MAX aircraft in its backlog, enough to keep the program busy into the 2030s at current production rates. The added line gives the manufacturer more room to work through those orders while reducing its dependence on three assembly lines at a single site.
The Everett line will also handle aircraft that require more time than Boeing’s standard production flow. Boeing said that could include jets with more complex interiors or additional work that would otherwise slow one of the Renton lines.
Boeing first announced the Everett expansion in January 2023. The factory had available space after the end of 747 production and the consolidation of 787 final assembly in South Carolina. Everett continues to build the 767 and 777 families.
The opening comes as Boeing works to rebuild 737 output following years of production interruptions and increased regulatory scrutiny.
The Federal Aviation Administration (FAA) imposed limits on 737 production after a door plug separated from an Alaska Airlines 737 MAX 9 shortly after takeoff in January 2024. Boeing has since been increasing output in stages while working with the FAA and suppliers.
Boeing said it will not move to higher production rates until the manufacturing system is stable and meeting its quality targets.
The company built the first 737 near Seattle before moving the program to Renton in 1970.