The names of regional synods below are links to that synod's website, at which one might find links to some classis websites.
Alberta Classis
British Columbia Classis
Ontario Classis
Albany Classis
Columbia-Greene Classis
Montgomery Classis
Rochester Classis
Schenectady Classis
Schoharie Classis
Brooklyn Classis
Mid-Hudson Classis
Nassau-Suffolk Classis
New York Classis
Orange Classis
Queens Classis
Rockland-Westchester Classis
Regional Synod of Mid-Atlantics
City Classis
Classis Delaware Raritan
Classis Greater Palisades
Classis New Brunswick
Classis Passaic Valley
Regional Synod of the Great Lakes
Great Lakes City Classis
Holland Classis
Muskegon Classis
North Grand Rapids Classis
Northern Michigan Classis
Southwest Michigan Classis
Zeeland Classis
Chicago Classis
Illiana Classis
Illinois Classis
Classis de la Naciones
(Churches in FL, GA, & the Global South)
Wisconsin Classis
Regional Synod of the Heartland
Central Iowa Classis
Central Plains Classis
Minnesota Classis
Pleasant Prairie Classis
East Sioux
West Sioux
Classis of Texas
Regional Synod of the Far West
Americas Classis
California Classis
Cascades Classis
Central California Classis
Rocky Mountain Classis
Southwest Classis
Peace to you.