- Alameda city is a city located in Alameda County, California, United States. It is located on Alameda Island and Bay Farm Island, adjacent to Oakland. Alameda city is known for its beautiful beaches, historic architecture, and charming downtown area. The city has a population of approximately 78,000 residents and offers a variety of recreational activities, including boating, cycling, and walking along the waterfront. Alameda city also has a strong naval history, as it was the site of a former naval air station.