From the Overview: "The Association of Southeast Asian Nations (ASEAN) is Southeast Asia's primary multilateral organization, a 10- member grouping of nations with a combined population of 650 million and a combined annual gross domestic product (GDP) of around $2.8 trillion in 2019. Established in 1967, it has grown into one of the world's largest regional fora, representing a strategically important region with some of the world's busiest sea lanes, including the Straits of Malacca and the South China Sea. Taken collectively, ASEAN would rank as the world's fifth-largest economy and the United States' fourth-largest export market."
CRS In Focus, IF10348
Congressional Research Service: https://crsreports.congress.gov/