Regions are composed of groups, intergroups, and service boards within specified geographic boundaries and the virtual community. OA is divided into eleven regions.
- OA Region One
Pacific North West: Alaska, Idaho, Montana, Oregon, Washington, Wyoming, Alberta, British Columbia, Northwest Territories, Saskatchewan, Yukon
- OA Region Two
Pacific Southwest: California, Hawaii, Reno/Tahoe area of Nevada, Mexico
- OA Region Three
Southwest: Arizona, Colorado, Nevada, New Mexico, Oklahoma, Texas, Utah
- OA Region Four
West Central: Illinois (except the Greater Chicago area and Central Illinois Intergroup), Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, South Dakota, Manitoba, Northwestern Ontario, the territory of Nunavut.
- OA Region Five
Central: Greater Chicago area and Central Illinois Intergroup, Indiana, Kentucky, Michigan, Ohio, Wisconsin, Southwestern Ontario
- OA Region Six
Northeast: Connecticut, Maine, Massachusetts, New Hampshire, New York, Rhode Island, Vermont, New Brunswick, Newfoundland and Labrador, Nova Scotia, Ontario, Prince Edward Island, Quebec, Bermuda
- OA Region Seven
Eastern: Delaware, District of Columbia, Maryland, New Jersey, Pennsylvania, Virginia, West Virginia
- OA Region Eight
Southeast: Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, Puerto Rico, South Carolina, Tennessee, the Virgin Islands, Central America, South America
- OA Region Nine
Countries and territories in Africa, Europe, the Middle East, Western Asia
- OA Region Ten
Countries and territories in Australia, New Zealand, South East Asia, the Western Pacific Basin
- OA Virtual Region
Virtual meetings and virtual intergroups.