Native Americans

• The Algonquian languages, a large phylum of Native American languages in eastern North America
• Algonquian peoples, those Native American tribes speaking Algonquian languages
• The Algonquin tribe, one tribe within the larger Algonquian group
• The Algonquin language, the language of the Algonquin tribe

(In all of the above cases, spellings in k and qu are equally acceptable. The variant Algonqui(a)n seems to be more common in the United States, while Algonki(a)n seems to be more common in English Canada.)

Place names

Canada

• Algonquin Park, a provincial park in Ontario
• Algonquin Island, part of Toronto, Ontario
• South Algonquin, Ontario
• Algonquin College, located in and around Ottawa, Ontario
• Algonquin Park, Manitoba
• The Algonquin, a hotel in St. Andrews, New Brunswick

United States

• Algonquin, Illinois
• Algonquin, Maryland
• Algonquin Peak, the second highest mountain in New York state
• The Algonquin Hotel, in New York City
• The Algonquin Round Table, an assemblage of literati that met at the Algonquin Hotel
• Algonquin Regional High School, located in Northborough, Massachusetts

Other

• HMCS Algonquin (DDH 283), an Iroquois-class destroyer of the Canadian Navy
• "USS Algonquin", the former name of the USS Accomac (YTL-18), a harbor tug of the United States Navy
• The Algonquin Regiment, an infantry regiment in the Canadian Forces
• Algonquin (horse), a skewbald pony belonging to the children of U.S. President Theodore Roosevelt.
• Algonquin Hotel, New York City
• Algonquin Round Table, a group of New York intellectuals
• Algonquin Club, Boston, Massachusetts
• Algonquin, an island in the fictional Liberty City of Grand Theft Auto IV based heavily on Manhattan.